Airflow-dependent deployable fences for aircraft wings

ABSTRACT

Airflow-dependent deployable fences for aircraft wings are described. An example apparatus includes a fence coupled to a wing of an aircraft. The fence is movable relative to the wing between a stowed position in which a panel of the fence extends along a skin of the wing, and a deployed position in which the panel extends at an upward angle away from the skin. The panel is configured to impede a spanwise airflow along the wing when the fence is in the deployed position. The fence is configured to move from the stowed position to the deployed position in response to an aerodynamic force exerted on a deployment vane of the fence.

FIELD OF THE DISCLOSURE

This disclosure relates generally to fences for aircraft wings and, morespecifically, to airflow-dependent deployable fences for aircraft wings.

BACKGROUND

Fences can be implemented on the wings of an aircraft (e.g., aswept-wing aircraft) to impede (e.g., block) spanwise airflows along thewings, thereby improving the handling of the aircraft at reduced speeds(e.g., a lower speed during a takeoff and/or landing operation of theaircraft relative to a higher speed during a cruise operation of theaircraft). Conventional fences are located on and/or arranged in agenerally chordwise direction along the topsides of the wings of theaircraft.

Some conventional fences are fixed in place on and/or non-movablycoupled to the wings of the aircraft, thereby causing such conventionalfences to generate and/or produce drag during the entirety of a flightof the aircraft (e.g., during a takeoff operation, during a cruiseoperation, and during a landing operation). Other conventional fencesare deployable and/or retractable between a vertical deployed positionextending upwardly from the wings of the aircraft and a vertical stowedposition within the airfoils of the wings of the aircraft, but typicallyrequire space-consuming mechanical linkages to actuate such movements ofthe fences, with such mechanical linkages being under the control of apilot of the aircraft.

SUMMARY

Example airflow-dependent deployable fences for aircraft wings aredisclosed herein. In some examples, an apparatus is disclosed. In someexamples, an apparatus is disclosed. In some disclosed examples, theapparatus comprises a fence coupled to a wing of an aircraft. In somedisclosed examples, the fence is movable relative to the wing between astowed position in which a panel of the fence extends along a skin ofthe wing, and a deployed position in which the panel extends at anupward angle away from the skin. In some disclosed examples, the panelis configured to impede a spanwise airflow along the wing when the fenceis in the deployed position. In some disclosed examples, the fence isconfigured to move from the stowed position to the deployed position inresponse to an aerodynamic force exerted on a deployment vane of thefence.

In some examples, a method for moving a fence coupled to a wing of anaircraft is disclosed. In some disclosed examples, the method comprisesmoving the fence between a stowed position in which a panel of the fenceextends along a skin of the wing, and a deployed position in which thepanel extends at an upward angle away from the skin. In some disclosedexamples, the panel impedes a spanwise airflow along the wing when thefence is in the deployed position. In some disclosed examples, themoving includes moving the fence from the stowed position to thedeployed position in response to an aerodynamic force exerted on adeployment vane of the fence.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example aircraft in which exampleairflow-dependent deployable fences can be implemented in accordancewith teachings of this disclosure.

FIG. 2 illustrates the example aircraft of FIG. 1 with the exampleairflow-dependent deployable fences of FIG. 1 deployed.

FIG. 3 is a cross-sectional view of the first example fence of FIGS. 1and 2 looking inboard and taken across the example central axis of theexample axle, with the first fence in the example stowed position ofFIG. 1.

FIG. 4 is a frontal view of the first example fence of FIGS. 1-3 lookingrearward along the example central axis of the example axle, with thefirst fence in the example stowed position of FIGS. 1 and 3.

FIG. 5 is a frontal view of the first example fence of FIGS. 1-4 lookingrearward along the example chordwise direction of the first examplewing, with the first fence in the example stowed position of FIGS. 1, 3and 4.

FIG. 6 is a plan view of the first example fence of FIGS. 1-5 in theexample stowed position of FIGS. 1 and 3-5.

FIG. 7 is a cross-sectional view of the first example fence of FIGS. 1-6looking inboard and taken across the example central axis of the exampleaxle, with the first fence in the example deployed position of FIG. 2.

FIG. 8 is a frontal view of the first example fence of FIGS. 1-7 lookingrearward along the example central axis of the example axle, with thefirst fence in the example deployed position of FIGS. 2 and 7.

FIG. 9 is a frontal view of the first example fence of FIGS. 1-8 lookingrearward along the example chordwise direction of the first examplewing, with the first fence in the example deployed position of FIGS. 2,7 and 8.

FIG. 10 is a plan view of the first example fence of FIGS. 1-9 in theexample deployed position of FIGS. 2 and 7-9.

FIG. 11 illustrates another example aircraft in which exampleairflow-dependent deployable fences can be implemented in accordancewith teachings of this disclosure.

FIG. 12 illustrates the example aircraft of FIG. 11 with the exampleairflow-dependent deployable fences of FIG. 11 deployed.

FIG. 13 is a cross-sectional view of the first example fence of FIGS. 11and 12 looking inboard and taken across the example central axis of theexample axle, with the first fence in the example stowed position ofFIG. 11.

FIG. 14 is a frontal view of the first example fence of FIGS. 11-13looking rearward along the example central axis of the example axle,with the first fence in the example stowed position of FIGS. 11 and 13.

FIG. 15 is a frontal view of the first example fence of FIGS. 11-14looking rearward along the example chordwise direction of the firstexample wing, with the first fence in the example stowed position ofFIGS. 11, 13 and 14.

FIG. 16 is a plan view of the first example fence of FIGS. 11-15 in theexample stowed position of FIGS. 11 and 13-15.

FIG. 17 is a cross-sectional view of the first example fence of FIGS.11-16 looking inboard and taken across the example central axis of theexample axle, with the first fence in the example deployed position ofFIG. 12.

FIG. 18 is a frontal view of the first example fence of FIGS. 11-17looking rearward along the example central axis of the example axle,with the first fence in the example deployed position of FIGS. 12 and17.

FIG. 19 is a frontal view of the first example fence of FIGS. 11-18looking rearward along the example chordwise direction of the firstexample wing, with the first fence in the example deployed position ofFIGS. 12, 17 and 18.

FIG. 20 is a plan view of the first example fence of FIGS. 11-19 in theexample deployed position of FIGS. 12 and 17-19.

FIG. 21 illustrates another example aircraft in which exampleairflow-dependent deployable fences can be implemented in accordancewith teachings of this disclosure.

FIG. 22 illustrates the example aircraft of FIG. 21 with the exampleairflow-dependent deployable fences of FIG. 21 deployed.

FIG. 23 is a cross-sectional view of the first example fence of FIGS. 21and 22 looking inboard and taken across the example central axis of theexample axle, with the first fence in the example stowed position ofFIG. 21.

FIG. 24 is a frontal view of the first example fence of FIGS. 21-23looking rearward along the example central axis of the example axle,with the first fence in the example stowed position of FIGS. 21 and 23.

FIG. 25 is a plan view of the first example fence of FIGS. 21-24 in theexample stowed position of FIGS. 21, 23 and 24.

FIG. 26 is a cross-sectional view of the first example fence of FIGS.21-25 looking inboard and taken across the example central axis of theexample axle, with the first fence in the example deployed position ofFIG. 22.

FIG. 27 is a frontal view of the first example fence of FIGS. 21-26looking rearward along the example central axis of the example axle,with the first fence in the example deployed position of FIGS. 22 and26.

FIG. 28 is a plan view of the first example fence of FIGS. 21-27 in theexample deployed position of FIGS. 22, 26 and 27.

FIG. 29 illustrates another example aircraft in which exampleairflow-dependent deployable fences can be implemented in accordancewith teachings of this disclosure.

FIG. 30 illustrates the example aircraft of FIG. 29 with the exampleairflow-dependent deployable fences of FIG. 29 deployed.

FIG. 31 is a cross-sectional view of the first example fence of FIGS. 29and 30 looking inboard and taken across the example central axis of theexample base, with the first fence in the example stowed position ofFIG. 29.

FIG. 32 is a frontal view of the first example fence of FIGS. 29-31looking rearward along the example central axis of the example base,with the first fence in the example stowed position of FIGS. 29 and 31.

FIG. 33 is a plan view of the first example fence of FIGS. 29-32 in theexample stowed position of FIGS. 29, 31 and 32.

FIG. 34 is a cross-sectional view of the first example fence of FIGS.29-33 looking inboard and taken across the example central axis of theexample base, with the first fence in the example deployed position ofFIG. 30.

FIG. 35 is a frontal view of the first example fence of FIGS. 29-34looking rearward along the example central axis of the example base,with the first fence in the example deployed position of FIGS. 30 and34.

FIG. 36 is a plan view of the first example fence of FIGS. 29-35 in theexample deployed position of FIGS. 30, 34 and 35.

FIG. 37 is a cross-sectional view of an example fence having a singleexample planar panel positioned in an example stowed position relativeto an example curved wing.

FIG. 38 is a cross-sectional view of an example fence having a pluralityof example planar panels respectively positioned in correspondingexample stowed positions relative to an example curved wing.

FIG. 39 is a cross-sectional view of the example fence of FIG. 38 havingthe plurality of example planar panels respectively positioned incorresponding example deployed positions relative to the example curvedwing of FIG. 38.

FIG. 40 is a cross-sectional view of an example fence having an exampleplurality of panels respectively positioned in corresponding examplerecessed stowed positions relative to an example curved wing.

FIG. 41 is a cross-sectional view of the example fence of FIG. 40 havingthe example plurality of panels respectively positioned in correspondingexample deployed positions relative to the example curved wing of FIG.40.

Certain examples are shown in the above-identified figures and describedin detail below. In describing these examples, like or identicalreference numbers are used to identify the same or similar elements. Thefigures are not necessarily to scale and certain features and certainviews of the figures may be shown exaggerated in scale or in schematicfor clarity and/or conciseness.

DETAILED DESCRIPTION

Fences can be implemented on the wings of an aircraft (e.g., aswept-wing aircraft) to impede (e.g., block) spanwise airflows along thewings, thereby improving the handling of the aircraft at reduced speeds(e.g., a lower speed during a takeoff and/or landing operation of theaircraft relative to a higher speed during a cruise operation of theaircraft). Conventional fences implemented on the wings of an aircrafttypically have substantial wetted areas that generate and/or producedrag while the aircraft is in flight.

Some conventional fences are fixed in place on and/or non-movablycoupled to the wings of the aircraft, thereby causing such conventionalfences to generate and/or produce drag during the entirety of a flightof the aircraft (e.g., during a takeoff operation, during a cruiseoperation, and during a landing operation). While implementing suchconventional fences on the wings of an aircraft to impede spanwiseairflows along the wings can advantageously improve the handling of theaircraft during low-speed operation (e.g., during takeoff and/orlanding), this advantage does not come without drawbacks. For example,the presence of such conventional fences can give rise to undesirableaerodynamic performance penalties (e.g., drag) during high-speedoperation of the aircraft (e.g., during cruise).

Other conventional fences are movable (e.g., deployable and/orretractable) between a vertical deployed position extending upwardlyfrom the wings of the aircraft and a vertical stowed position within theairfoils of the wings of the aircraft. While implementing such movableconventional fences on the wings of an aircraft to impede spanwiseairflows along the wings can advantageously improve the handling of theaircraft during low-speed operation (e.g., during takeoff and/orlanding), this advantage again does not come without drawbacks. Forexample, such movable conventional fences typically requirespace-consuming in-wing mechanical linkages to actuate and/or move thefences between their respective deployed and stowed positions, with suchmechanical linkages being under the control of a pilot of the aircraft.

Absent the implementation of conventional fences as described above, anaircraft typically requires the implementation of one or more othercountermeasure(s) to mitigate spanwise airflows along the wings of theaircraft during low-speed operation. Known countermeasures undesirablyincrease the costs associated with designing, testing, installing and/orotherwise implementing the wings and/or, more generally, the aircraft.

Unlike the conventional fences and/or other countermeasures describedabove, example deployable fences disclosed herein are aerodynamicallyactivated and/or airflow dependent. In some disclosed examples, adeployable fence is coupled (e.g., rotatably coupled) to a wing of anaircraft such that the fence is advantageously movable relative to thewing between a stowed position in which a panel of the fence extendsalong a skin of the wing, and a deployed position in which the panelextends at an upward angle away from the skin. The panel is configuredto impact the airflow around the aircraft when the fence is in thedeployed position. For example, the panel can impede a spanwise airflowalong the wing when the fence is in the deployed position. As anotherexample, the panel can initiate and/or generate a vortex along the wingwhen the fence is in the deployed position. The fence is advantageouslyconfigured to move between the stowed position and the deployed positionin response to an aerodynamic force exerted on the fence. In somedisclosed examples, the fence is configured to move from the deployedposition to the stowed position in response to an aerodynamic forceexerted on the panel. In other disclosed examples, the fence isconfigured to move from the stowed position to the deployed position inresponse to an aerodynamic force exerted on a deployment vane of thefence.

The example airflow-dependent deployable fences disclosed herein providenumerous advantages over the conventional fences described above. Forexample, the movability (e.g., movement from a deployed position to astowed position) of the airflow-dependent deployable fences disclosedherein advantageously reduces undesirable aerodynamic performancepenalties (e.g., drag) during high-speed operation of the aircraft(e.g., during cruise). As another example, the airflow-dependentdeployable fences disclosed herein provide a stowed position for thefence whereby the fence extends along the skin of the wing (as opposedto vertically within the wing), thereby advantageously increasing theamount of unused space within the wing relative to the amount of spacethat may otherwise be consumed by the in-wing mechanical linkagesassociated with the above-described vertically-deployable conventionalfences. As yet another example, the airflow-dependent deployable fencesdisclosed herein facilitate pilot-free operation (e.g., deployment andretraction) of the fences, which advantageously ensures that the fencesare deployed and/or retracted at the appropriate time(s) and/or underthe appropriate flight condition(s).

FIG. 1 illustrates an example aircraft 100 in which exampleairflow-dependent deployable fences can be implemented in accordancewith teachings of this disclosure. FIG. 1 illustrates the exampleaircraft 100 of FIG. 1 with the example airflow-dependent deployablefences of FIG. 1 stowed. FIG. 2 illustrates the example aircraft 100 ofFIG. 1 with the example airflow-dependent deployable fences of FIG. 1deployed. The aircraft 100 can be any form and/or type of aircraftincluding, for example, a civil (e.g., business or commercial) aircraft,a military aircraft, a manned (e.g., piloted) aircraft, an unmannedaircraft (e.g., a drone), etc. In the illustrated example of FIGS. 1 and2, the aircraft 100 includes an example fuselage 102, a first examplewing 104 (e.g., a left-side wing), a second example wing 106 (e.g., aright-side wing), a first example fence 108 (e.g., a left-side fence),and a second example fence 110 (e.g., a right-side fence). Although theillustrated example of FIGS. 1 and 2 depicts only a single fence locatedon each wing of the aircraft 100 (e.g., the first fence 108 located onthe first wing 104, and the second fence 110 located on the second wing106), other example implementations can include multiple (e.g., 2, 3, 4,etc.) fences located on each wing of the aircraft 100. In some examples,the location(s), size(s), and/or shape(s) of respective ones of thefences (e.g., the first fence 108 and the second fence 110) of theaircraft 100 can differ relative to the location(s), size(s) and/orshape(s) of the fences shown in FIGS. 1 and 2.

The fuselage 102 of FIGS. 1 and 2 has a generally cylindrical shape thatdefines an example longitudinal axis 112 of the aircraft 100. The firstwing 104 and the second wing 106 of FIGS. 1 and 2 are respectivelycoupled to the fuselage 102 and swept in a rearward direction of theaircraft 100. The first wing 104 includes an example skin 114 forming(e.g., forming all or part of) an outer surface of the first wing 104,and the second wing 106 includes an example skin 116 forming (e.g.,forming all or part of) an outer surface of the second wing 106.

The first wing 104 of FIGS. 1 and 2 defines an example spanwisedirection 118 moving from an example inboard portion 120 (e.g., inboardrelative to the spanwise location of the first fence 108) of the firstwing 104 toward an example outboard portion 122 (e.g., outboard relativeto the spanwise location of the first fence 108) of the first wing 104.The spanwise direction 118 defined by the first wing 104 isrepresentative of a direction of a spanwise airflow that may occur alongthe first wing 104. The first wing 104 also defines an example chordwisedirection 124 moving from an example leading edge 126 of the first wing104 toward an example trailing edge 128 of the first wing 104. Thechordwise direction 124 defined by the first wing 104 is representativeof a direction of a chordwise airflow (e.g., a cruise airflow) that mayoccur along the first wing 104.

The second wing 106 of FIGS. 1 and 2 defines an example spanwisedirection 130 moving from an example inboard portion 132 (e.g., inboardrelative to the spanwise location of the second fence 110) of the secondwing 106 toward an example outboard portion 134 (e.g., outboard relativeto the spanwise location of the second fence 110) of the second wing106. The spanwise direction 130 defined by the second wing 106 isrepresentative of a direction of a spanwise airflow that may occur alongthe second wing 106. The second wing 106 also defines an examplechordwise direction 136 moving from an example leading edge 138 of thesecond wing 106 toward an example trailing edge 140 of the second wing106. The chordwise direction 136 defined by the second wing 106 isrepresentative of a direction of a chordwise airflow (e.g., a cruiseairflow) that may occur along the second wing 106.

The first fence 108 of FIGS. 1 and 2 is rotatably coupled to the firstwing 104 such that the first fence 108 is movable (e.g., rotatable)between the stowed position shown in FIG. 1 and the deployed positionshown in FIG. 2. The first fence 108 includes an example panel 142. Thepanel 142 of the first fence 108 extends (e.g., in an inboard directiontoward the longitudinal axis 112) along the skin 114 of the first wing104 when the first fence 108 is in the stowed position shown in FIG. 1.In some examples, the panel 142 of the first fence 108 extends along andis positioned over and/or on top of the skin 114 of the first wing 104when the first fence 108 is in the stowed position shown in FIG. 1. Inother examples, the panel 142 of the first fence 108 extends along andis recessed (e.g., fully or partially recessed) relative to the skin 114of the first wing 104 when the first fence 108 is in the stowed positionshown in FIG. 1. The panel 142 of the first fence 108 extends at anupward angle (e.g., vertically) away from the skin 114 of the first wing104 when the first fence 108 is in the deployed position shown in FIG.2. The panel 142 of the first fence 108 is configured to impact theairflow around the aircraft 100 when the first fence 108 is in thedeployed position shown in FIG. 2. For example, the panel 142 can impedea spanwise airflow occurring along the spanwise direction 118 of thefirst wing 104 when the first fence 108 is in the deployed positionshown in FIG. 2. As another example, the panel 142 can initiate and/orgenerate a vortex along the first wing 104 when the first fence 108 isin the deployed position shown in FIG. 2.

The panel 142 and/or, more generally, the first fence 108 of FIGS. 1 and2 is rotatably coupled to the first wing 104 of FIGS. 1 and 2 via anexample axle 144 having an example central axis 146. In the illustratedexample of FIGS. 1 and 2, the central axis 146 of the axle 144 is canted(e.g., oriented at an angle) relative to the chordwise direction 124 ofthe first wing 104. For example, as shown in FIGS. 1 and 2, the centralaxis 146 of the axle 144 is canted at an example toe-in angle 148relative to the chordwise direction 124 of the first wing 104 such thata first end of the axle 144 positioned toward the leading edge 126 ofthe first wing 104 is located closer to the longitudinal axis 112 of theaircraft 100 than is a second end of the axle 144 positioned toward thetrailing edge 128 of the first wing 104. The example toe-in angle 148shown in FIGS. 1 and 2 is exaggerated for clarity. When implemented, thetoe-in angle 148 preferably has a value ranging from one to fifteendegrees.

The first fence 108 of FIGS. 1 and 2 is configured to move from thedeployed position shown in FIG. 2 to the stowed position shown in FIG. 1in response to an aerodynamic force exerted on the panel 142 of thefirst fence 108. In some examples, the aerodynamic force may begenerated via a chordwise airflow (e.g., a cruise airflow) occurringalong the chordwise direction 124 of the first wing 104. In someexamples, an actuator operatively coupled to the first fence 108 biasesand/or maintains the first fence 108 in the deployed position shown inFIG. 2 in response to the aerodynamic force exerted on the panel 142 ofthe first fence 108 being less than a threshold force value (e.g., lessthan the biasing force generated by the actuator). Example means forimplementing the actuator are discussed below in connection with FIGS.3-10. In some disclosed examples, the first fence 108 moves from thedeployed position shown in FIG. 2 to the stowed position shown in FIG. 1in response to the aerodynamic force exerted on the panel 142 of thefirst fence 108 being greater than the threshold force value (e.g.,greater than the biasing force generated by the actuator). In somedisclosed examples, the first fence 108 is configured to move from thedeployed position shown in FIG. 2 to the stowed position shown in FIG. 1during a cruise operation of the aircraft 100 having a first speed, andthe first fence 108 is further configured to move from the stowedposition shown in FIG. 1 to the deployed position shown in FIG. 2 duringa reduced speed operation (e.g., a takeoff or landing operation) of theaircraft 100 having a second speed less than the first speed.

The second fence 110 of FIGS. 1 and 2 is rotatably coupled to the secondwing 106 such that the second fence 110 is movable (e.g., rotatable)between the stowed position shown in FIG. 1 and the deployed positionshown in FIG. 2. The second fence 110 includes an example panel 150. Thepanel 150 of the second fence 110 extends (e.g., in an inboard directiontoward the longitudinal axis 112) along the skin 116 of the second wing106 when the second fence 110 is in the stowed position shown in FIG. 1.In some examples, the panel 150 of the second fence 110 extends alongand is positioned over and/or on top of the skin 116 of the second wing106 when the second fence 110 is in the stowed position shown in FIG. 1.In other examples, the panel 150 of the second fence 110 extends alongand is recessed (e.g., fully or partially recessed) relative to the skin116 of the second wing 106 when the second fence 110 is in the stowedposition shown in FIG. 1. The panel 150 of the second fence 110 extendsat an upward angle (e.g., vertically) away from the skin 116 of thesecond wing 106 when the second fence 110 is in the deployed positionshown in FIG. 2. The panel 150 of the second fence 110 is configured toimpact the airflow around the aircraft 100 when the second fence 110 isin the deployed position shown in FIG. 2. For example, the panel 150 canimpede a spanwise airflow occurring along the spanwise direction 130 ofthe second wing 106 when the second fence 110 is in the deployedposition shown in FIG. 2. As another example, the panel 150 can initiateand/or generate a vortex along the second wing 106 when the second fence110 is in the deployed position shown in FIG. 2.

The panel 150 and/or, more generally, the second fence 110 of FIGS. 1and 2 is rotatably coupled to the second wing 106 of FIGS. 1 and 2 viaan example axle 152 having an example central axis 154. In theillustrated example of FIGS. 1 and 2, the central axis 154 of the axle152 is canted (e.g., oriented at an angle) relative to the chordwisedirection 136 of the second wing 106. For example, as shown in FIGS. 1and 2, the central axis 154 of the axle 152 is canted at an exampletoe-in angle 156 relative to the chordwise direction 136 of the secondwing 106 such that a first end of the axle 152 positioned toward theleading edge 138 of the second wing 106 is located closer to thelongitudinal axis 112 of the aircraft 100 than is a second end of theaxle 152 positioned toward the trailing edge 140 of the second wing 106.The example toe-in angle 156 shown in FIGS. 1 and 2 is exaggerated forclarity. When implemented, the toe-in angle 156 preferably has a valueranging from one to fifteen degrees.

The second fence 110 of FIGS. 1 and 2 is configured to move from thedeployed position shown in FIG. 2 to the stowed position shown in FIG. 1in response to an aerodynamic force exerted on the panel 150 of thesecond fence 110. In some examples, the aerodynamic force may begenerated via a chordwise airflow (e.g., a cruise airflow) occurringalong the chordwise direction 136 of the second wing 106. In someexamples, an actuator operatively coupled to the second fence 110 biasesand/or maintains the second fence 110 in the deployed position shown inFIG. 2 in response to the aerodynamic force exerted on the panel 150 ofthe second fence 110 being less than a threshold force value (e.g., lessthan the biasing force generated by the actuator). Example means forimplementing the actuator are discussed below in connection with FIGS.3-10. In some disclosed examples, the second fence 110 moves from thedeployed position shown in FIG. 2 to the stowed position shown in FIG. 1in response to the aerodynamic force exerted on the panel 150 of thesecond fence 110 being greater than the threshold force value (e.g.,greater than the biasing force generated by the actuator). In somedisclosed examples, the second fence 110 is configured to move from thedeployed position shown in FIG. 2 to the stowed position shown in FIG. 1during a cruise operation of the aircraft 100 having a first speed, andthe second fence 110 is further configured to move from the stowedposition shown in FIG. 1 to the deployed position shown in FIG. 2 duringa reduced speed operation (e.g., a takeoff or landing operation) of theaircraft 100 having a second speed less than the first speed.

FIGS. 3-10 provide additional views of the first example fence 108 ofFIGS. 1 and 2 rotatably coupled to the first example wing 104 of FIGS. 1and 2. More specifically, FIG. 3 is a cross-sectional view of the firstexample fence 108 of FIGS. 1 and 2 looking inboard and taken across theexample central axis 146 of the example axle 144, with the first fence108 in the example stowed position of FIG. 1. FIG. 4 is a frontal viewof the first example fence 108 of FIGS. 1-3 looking rearward along theexample central axis 146 of the example axle 144, with the first fence108 in the example stowed position of FIGS. 1 and 3. FIG. 5 is a frontalview of the first example fence 108 of FIGS. 1-4 looking rearward alongthe example chordwise direction 124 of the first example wing 104, withthe first fence 108 in the example stowed position of FIGS. 1, 3 and 4.FIG. 6 is a plan view of the first example fence 108 of FIGS. 1-5 in theexample stowed position of FIGS. 1 and 3-5. FIG. 7 is a cross-sectionalview of the first example fence 108 of FIGS. 1-6 looking inboard andtaken across the example central axis 146 of the example axle 144, withthe first fence 108 in the example deployed position of FIG. 2. FIG. 8is a frontal view of the first example fence 108 of FIGS. 1-7 lookingrearward along the example central axis 146 of the example axle 144,with the first fence 108 in the example deployed position of FIGS. 2 and7. FIG. 9 is a frontal view of the first example fence 108 of FIGS. 1-8looking rearward along the example chordwise direction 124 of the firstexample wing 104, with the first fence 108 in the example deployedposition of FIGS. 2, 7 and 8. FIG. 10 is a plan view of the firstexample fence 108 of FIGS. 1-9 in the example deployed position of FIGS.2 and 7-9.

In the illustrated example of FIGS. 3-10, the first fence 108 isrotatably coupled to the first wing 104 via the axle 144. The axle 144includes a first example end 302 coupled to the first wing 104 via afirst example axle mount 304, and further includes a second example end306 located opposite the first end 302 and coupled to the first wing 104via a second example axle mount 308. The first end 302 of the axle 144is positioned toward the leading edge 126 of the first wing 104 and/ortoward the first axle mount 304, and the second end 306 of the axle 144is positioned toward the trailing edge 128 of the first wing 104 and/ortoward the second axle mount 308.

The first fence 108 includes a first example end 310, a second exampleend 312 located opposite the first end 310, and an example through hole314 extending between the first end 310 and the second end 312 of thefirst fence 108. The first end 310 of the first fence 108 is positionedtoward the leading edge 126 of the first wing 104 and/or toward thefirst axle mount 304, and the second end 312 of the first fence 108 ispositioned toward the trailing edge 128 of the first wing 104 and/ortoward the second axle mount 308. The axle 144 passes and/or extendsthrough the through hole 314 of the first fence 108 such that the axle144 and the through hole 314 are parallel and/or coaxially located, andsuch that the first fence 108 is secured to the axle 144 via the firstaxle mount 304 and the second axle mount 308. The first axle mount 304and the second axle mount 308 accordingly secure both the axle 144 andthe first fence 108 to the first wing 104. The first fence 108 isrotatable about the axle 144, and is also rotatable relative to thefirst wing 104. For example, the first fence 108 is rotatable about theaxle 144 relative to the first wing 104 between the stowed positionshown in FIGS. 1 and 3-6 and the deployed position shown in FIGS. 2 and7-10.

In the illustrated example of FIGS. 3-10, the panel 142 of the firstfence 108 extends in an inboard direction (e.g., toward the longitudinalaxis 112 of the aircraft 100) along the skin 114 of the first wing 104when the first fence 108 is in the stowed position shown in FIGS. 3-6.As shown in FIGS. 3-6, the panel 142 of the first fence 108 extendsalong and is positioned over and/or on top of the skin 114 of the firstwing 104 when the first fence 108 is in the stowed position. In otherexamples, the panel 142 of the first fence 108 can extend along and berecessed (e.g., fully or partially recessed) relative to the skin 114 ofthe first wing 104 when the first fence 108 is in the stowed position.As shown in FIGS. 7-10, the panel 142 of the first fence 108 extends atan upward angle (e.g., vertically) away from the skin 114 of the firstwing 104 when the first fence 108 is in the deployed position. The panel142 of the first fence 108 is configured to impact the airflow aroundthe aircraft 100 when the first fence 108 is in the deployed positionshown in FIGS. 7-10. For example, the panel 142 can impede a spanwiseairflow occurring along the spanwise direction 118 of the first wing 104when the first fence 108 is in the deployed position shown in FIGS.7-10. As another example, the panel 142 can initiate and/or generate avortex along the first wing 104 when the first fence 108 is in thedeployed position shown in FIGS. 7-10.

In the illustrated example of FIGS. 3-10, the panel 142 of the firstfence 108 is planar. In other examples, the panel 142 of the first fence108 can be non-planar. For example, the panel 142 of the first fence 108can have a non-planar (e.g., curved) aerodynamic shape. In someexamples, the non-planar aerodynamic shape can be configured to matchand/or mimic a non-planar (e.g., curved) aerodynamic shape of the firstwing 104. In the illustrated example of FIGS. 3-10, the panel 142 of thefirst fence 108 has a trapezoidal shape between the first end 310 of thefirst fence 108 and the second end 312 of the first fence 108. In otherexamples, the panel 142 of the first fence 108 can have a different(e.g., non-trapezoidal) shape between the first end 310 of the firstfence 108 and the second end 312 of the first fence 108. For example,the panel 142 of the first fence 108 can have any of a rectangularshape, a square shape, a triangular shape, a semicircular shape, acircular shape, or an elliptical shape, among others, between the firstend 310 of the first fence 108 and the second end 312 of the first fence108.

In the illustrated example of FIGS. 3-10, an example spring-loaded axle316 is formed via the axle 144 and an example spring 318 coiled around aportion of the axle 144. As further described below, the spring 318and/or, more generally, the spring-loaded axle 316 function(s) and/oroperate(s) as an actuator configured to move the first fence 108 betweenthe stowed position shown in FIGS. 3-6 and the deployed position shownin FIGS. 7-10, dependent upon the direction and/or strength of airflowscaught by and/or received at the panel 142 of the first fence 108. Inthe illustrated example of FIGS. 3-10, the spring 318 of thespring-loaded axle 316 is located between the second end 312 of thefirst fence 108 and the second axle mount 308. The spring 318 and/or,more generally, the spring-loaded axle 316 is/are operatively coupled tothe first fence 108 such that the spring 318 and/or the spring-loadedaxle 316 bias(es) the first fence 108 to the deployed position shown inFIGS. 7-10. For example, the spring 318 of the spring-loaded axle 316generates a restoring force (e.g., a biasing force) having a restoringforce value. In the absence of a deflecting force (e.g., acounter-biasing force, as may be generated via a chordwise and/or cruiseairflow) opposing the restoring force and having a deflecting forcevalue that is greater than the restoring force value, the restoringforce generated via the spring 318 moves (e.g., rotates) the first fence108 to, and/or maintains the first fence 108 in, the deployed positionshown in FIGS. 7-10.

In the illustrated example of FIGS. 3-10, the spring 318 is in arelatively more wound state when the first fence 108 is in the stowedposition shown in FIGS. 3-6 compared to when the first fence 108 is inthe deployed position shown in FIGS. 7-10. Conversely, the spring 318 isin a relatively more unwound state when the first fence 108 is in thedeployed position shown in FIGS. 7-10 compared to when the first fence108 is in the stowed position shown in FIGS. 3-6. Stated differently,the spring 318 winds around the spring-loaded axle 316 as the firstfence 108 moves from the deployed position shown in FIGS. 7-10 to thestowed position shown in FIGS. 3-6, and the spring 318 converselyunwinds around the spring-loaded axle 316 as the first fence 108 movesfrom the stowed position shown in FIGS. 3-6 to the deployed positionshown in FIGS. 7-10. In the illustrated example of FIGS. 3-10, thespring 318 is implemented via one or more torsion spring(s). In otherexamples, the spring 318 may additionally or alternatively beimplemented via one or more (e.g., individually or in combination)suitably arranged leaf spring(s), compression spring(s), and/or tensionspring(s).

Movement (e.g., rotation) of the first fence 108 relative to the firstwing 104 is airflow dependent. For example, as described above inconnection with FIGS. 1 and 2 and further shown in FIGS. 3-10, thecentral axis 146 of the axle 144 is canted at the toe-in angle 148relative to the chordwise direction 124 of the first wing 104.Positioning and/or orienting the central axis 146 of the axle 144 at thetoe-in angle 148 causes the panel 142 of the first fence 108 to bepositioned and/or oriented in a similar manner. When the first fence 108is in the deployed position shown in FIGS. 7-10 (e.g., as may be causedby the restoring force generated by the spring 318 of the spring-loadedaxle 316), the panel 142 of the first fence 108 is positioned to catch,receive and/or react to a chordwise airflow (e.g., a cruise airflow)occurring along the chordwise direction 124 of the first wing 104. As aresult of the toe-in angle 148 at which the central axis 146 of the axle144 is canted, the chordwise airflow occurring along the chordwisedirection 124 of the first wing 104 carries a deflecting force componentthat counteracts (e.g., opposes) the restoring force generated by thespring 318 of the spring-loaded axle 316.

If the deflecting force component of the chordwise airflow received at,applied to, and/or exerted on the panel 142 of the first fence 108 isgreater than the restoring force generated by the spring 318 of thespring-loaded axle 316, the chordwise airflow moves the first fence 108from the deployed position shown in FIGS. 7-10 to the stowed positionshown in FIGS. 3-6. If the deflecting force component of the chordwiseairflow received at, applied to, and/or exerted on the panel 142 of thefirst fence 108 is instead less than the restoring force generated bythe spring 318 of the spring-loaded axle 316, the spring 318 maintainsthe first fence 108 in the deployed position shown in FIGS. 7-10, and/ormoves the first fence 108 from the stowed position shown in FIGS. 3-6 tothe deployed position shown in FIGS. 7-10. Movement of the first fence108 relative to the first wing 104 is accordingly dependent on thepresence or absence of the chordwise airflow, and on the relativestrength (e.g., force) of such airflow.

In some examples, the first fence 108 is configured to move from thedeployed position shown in FIGS. 7-10 to the stowed position shown inFIGS. 3-6 during a cruise operation of the aircraft 100 having a firstspeed, and the first fence 108 is further configured to move from thestowed position of FIGS. 3-6 to the deployed position of FIGS. 7-10during a reduced speed operation (e.g., a takeoff or landing operation)of the aircraft 100 having a second speed less than the first speed. Forexample, the spring 318 of the spring-loaded axle 316 may be configuredand/or implemented to have a spring constant that causes the spring 318to generate a restoring force sufficient to move the first fence 108 to,and/or sufficient to maintain the first fence 108 in, the deployedposition shown in FIGS. 7-10 when the aircraft 100 is traveling at aspeed less than a speed threshold (e.g., less than a cruise speed). Whenthe aircraft 100 is traveling at a speed above or equal to the speedthreshold, the restoring force generated by the spring 318 of thespring-loaded axle 316 is overcome via a deflecting force, and the firstfence 108 accordingly moves from the deployed position shown in FIGS.7-10 to the stowed position shown in FIGS. 3-6.

While FIGS. 3-10 and the descriptions thereof provided above aredirected to the actuator of the first fence 108 being implemented as aspring-loaded axle (e.g., spring-loaded axle 316) configured to biasand/or move the first fence 108 from the stowed position shown in FIGS.3-6 to the deployed position shown in FIGS. 7-10, the actuator of thefirst fence 108 can be implemented in other forms including, forexample, electrical, hydraulic, pneumatic, motor-driven, and/or shapememory alloy actuators. Furthermore, while FIGS. 3-10 and thedescriptions thereof provided above are directed to the first fence 108of FIGS. 1 and 2 that is rotatably coupled to the first wing 104 ofFIGS. 1 and 2, the informed reader will recognize that the second fence110 of FIGS. 1 and 2 that is rotatably coupled to the second wing 106 ofFIGS. 1 and 2 can be similarly implemented (e.g., in a manner that ismirrored about the longitudinal axis 112 of the aircraft 100). Moreover,while FIGS. 3-10 and the descriptions thereof provided above aredirected to the first fence 108 of FIGS. 1 and 2 that is rotatablycoupled to the first wing 104 of FIGS. 1 and 2, the informed reader willrecognize that any number of additional fences can be similarlyimplemented on the first wing 104.

FIG. 11 illustrates another example aircraft 1100 in which exampleairflow-dependent deployable fences can be implemented in accordancewith teachings of this disclosure. FIG. 11 illustrates the exampleaircraft 1100 of FIG. 11 with the example airflow-dependent deployablefences of FIG. 11 stowed. FIG. 12 illustrates the example aircraft 1100of FIG. 11 with the example airflow-dependent deployable fences of FIG.11 deployed. The aircraft 1100 can be any form and/or type of aircraftincluding, for example, a civil (e.g., business or commercial) aircraft,a military aircraft, a manned (e.g., piloted) aircraft, an unmannedaircraft (e.g., a drone), etc. In the illustrated example of FIGS. 11and 12, the aircraft 1100 includes an example fuselage 1102, a firstexample wing 1104 (e.g., a left-side wing), a second example wing 1106(e.g., a right-side wing), a first example fence 1108 (e.g., a left-sidefence), and a second example fence 1110 (e.g., a right-side fence).Although the illustrated example of FIGS. 11 and 12 depicts only asingle fence located on each wing of the aircraft 1100 (e.g., the firstfence 1108 located on the first wing 1104, and the second fence 1110located on the second wing 1106), other example implementations caninclude multiple (e.g., 2, 3, 4, etc.) fences located on each wing ofthe aircraft 1100. In some examples, the location(s), size(s), and/orshape(s) of respective ones of the fences (e.g., the first fence 1108and the second fence 1110) of the aircraft 1100 can differ relative tothe location(s), size(s) and/or shape(s) of the fences shown in FIGS. 11and 12.

The fuselage 1102 of FIGS. 11 and 12 has a generally cylindrical shapethat defines an example longitudinal axis 1112 of the aircraft 1100. Thefirst wing 1104 and the second wing 1106 of FIGS. 11 and 12 arerespectively coupled to the fuselage 1102 and swept in a rearwarddirection of the aircraft 1100. The first wing 1104 includes an exampleskin 1114 forming (e.g., forming all or part of) an outer surface of thefirst wing 1104, and the second wing 1106 includes an example skin 1116forming (e.g., forming all or part of) an outer surface of the secondwing 1106.

The first wing 1104 of FIGS. 11 and 12 defines an example spanwisedirection 1118 moving from an example inboard portion 1120 (e.g.,inboard relative to the spanwise location of the first fence 1108) ofthe first wing 1104 toward an example outboard portion 1122 (e.g.,outboard relative to the spanwise location of the first fence 1108) ofthe first wing 1104. The spanwise direction 1118 defined by the firstwing 1104 is representative of a direction of a spanwise airflow thatmay occur along the first wing 1104. The first wing 1104 also defines anexample chordwise direction 1124 moving from an example leading edge1126 of the first wing 1104 toward an example trailing edge 1128 of thefirst wing 1104. The chordwise direction 1124 defined by the first wing1104 is representative of a direction of a chordwise airflow (e.g., acruise airflow) that may occur along the first wing 1104.

The second wing 1106 of FIGS. 11 and 12 defines an example spanwisedirection 1130 moving from an example inboard portion 1132 (e.g.,inboard relative to the spanwise location of the second fence 1110) ofthe second wing 1106 toward an example outboard portion 1134 (e.g.,outboard relative to the spanwise location of the second fence 1110) ofthe second wing 1106. The spanwise direction 1130 defined by the secondwing 1106 is representative of a direction of a spanwise airflow thatmay occur along the second wing 1106. The second wing 1106 also definesan example chordwise direction 1136 moving from an example leading edge1138 of the second wing 1106 toward an example trailing edge 1140 of thesecond wing 1106. The chordwise direction 1136 defined by the secondwing 1106 is representative of a direction of a chordwise airflow (e.g.,a cruise airflow) that may occur along the second wing 1106.

The first fence 1108 of FIGS. 11 and 12 is rotatably coupled to thefirst wing 1104 such that the first fence 1108 is movable (e.g.,rotatable) between the stowed position shown in FIG. 11 and the deployedposition shown in FIG. 12. The first fence 1108 includes an examplepanel 1142. The panel 1142 of the first fence 1108 extends (e.g., in anoutboard direction away from the longitudinal axis 112) along the skin1114 of the first wing 1104 when the first fence 1108 is in the stowedposition shown in FIG. 11. In some examples, the panel 1142 of the firstfence 1108 extends along and is positioned over and/or on top of theskin 1114 of the first wing 1104 when the first fence 1108 is in thestowed position shown in FIG. 11. In other examples, the panel 1142 ofthe first fence 1108 extends along and is recessed (e.g., fully orpartially recessed) relative to the skin 1114 of the first wing 1104when the first fence 1108 is in the stowed position shown in FIG. 11.The panel 1142 of the first fence 1108 extends at an upward angle (e.g.,vertically) away from the skin 1114 of the first wing 1104 when thefirst fence 1108 is in the deployed position shown in FIG. 12. The panel1142 of the first fence 1108 is configured to impact the airflow aroundthe aircraft 1100 when the first fence 1108 is in the deployed positionshown in FIG. 12. For example, the panel 1142 can impede a spanwiseairflow occurring along the spanwise direction 1118 of the first wing1104 when the first fence 1108 is in the deployed position shown in FIG.12. As another example, the panel 1142 can initiate and/or generate avortex along the first wing 1104 when the first fence 1108 is in thedeployed position shown in FIG. 12.

The panel 1142 and/or, more generally, the first fence 1108 of FIGS. 11and 12 is rotatably coupled to the first wing 1104 of FIGS. 11 and 12via an example axle 1144 having an example central axis 1146. In theillustrated example of FIGS. 11 and 12, the central axis 1146 of theaxle 1144 is canted (e.g., oriented at an angle) relative to thechordwise direction 1124 of the first wing 1104. For example, as shownin FIGS. 11 and 12, the central axis 1146 of the axle 1144 is canted atan example toe-out angle 1148 relative to the chordwise direction 1124of the first wing 1104 such that a first end of the axle 1144 positionedtoward the leading edge 1126 of the first wing 1104 is located furtheraway from the longitudinal axis 1112 of the aircraft 1100 than is asecond end of the axle 1144 positioned toward the trailing edge 1128 ofthe first wing 1104. The example toe-out angle 1148 shown in FIGS. 11and 12 is exaggerated for clarity. When implemented, the toe-out angle1148 preferably has a value ranging from one to fifteen degrees.

The first fence 1108 of FIGS. 11 and 12 is configured to move from thedeployed position shown in FIG. 12 to the stowed position shown in FIG.11 in response to an aerodynamic force exerted on the panel 1142 of thefirst fence 1108. In some examples, the aerodynamic force may begenerated via a chordwise airflow (e.g., a cruise airflow) occurringalong the chordwise direction 1124 of the first wing 1104. In someexamples, an actuator operatively coupled to the first fence 1108 biasesand/or maintains the first fence 1108 in the deployed position shown inFIG. 12 in response to the aerodynamic force exerted on the panel 1142of the first fence 1108 being less than a threshold force value (e.g.,less than the biasing force generated by the actuator). Example meansfor implementing the actuator are discussed below in connection withFIGS. 13-20. In some disclosed examples, the first fence 1108 moves fromthe deployed position shown in FIG. 12 to the stowed position shown inFIG. 11 in response to the aerodynamic force exerted on the panel 1142of the first fence 1108 being greater than the threshold force value(e.g., greater than the biasing force generated by the actuator). Insome disclosed examples, the first fence 1108 is configured to move fromthe deployed position shown in FIG. 12 to the stowed position shown inFIG. 11 during a cruise operation of the aircraft 1100 having a firstspeed, and the first fence 1108 is further configured to move from thestowed position shown in FIG. 11 to the deployed position shown in FIG.12 during a reduced speed operation (e.g., a takeoff or landingoperation) of the aircraft 1100 having a second speed less than thefirst speed.

The second fence 1110 of FIGS. 11 and 12 is rotatably coupled to thesecond wing 1106 such that the second fence 1110 is movable (e.g.,rotatable) between the stowed position shown in FIG. 11 and the deployedposition shown in FIG. 12. The second fence 1110 includes an examplepanel 1150. The panel 1150 of the second fence 1110 extends (e.g., in anoutboard direction away from the longitudinal axis 1112) along the skin1116 of the second wing 1106 when the second fence 1110 is in the stowedposition shown in FIG. 11. In some examples, the panel 1150 of thesecond fence 1110 extends along and is positioned over and/or on top ofthe skin 1116 of the second wing 1106 when the second fence 1110 is inthe stowed position shown in FIG. 11. In other examples, the panel 1150of the second fence 1110 extends along and is recessed (e.g., fully orpartially recessed) relative to the skin 1116 of the second wing 1106when the second fence 1110 is in the stowed position shown in FIG. 11.The panel 1150 of the second fence 1110 extends at an upward angle(e.g., vertically) away from the skin 1116 of the second wing 1106 whenthe second fence 1110 is in the deployed position shown in FIG. 12. Thepanel 1150 of the second fence 1110 is configured to impact the airflowaround the aircraft 1100 when the second fence 1110 is in the deployedposition shown in FIG. 12. For example, the panel 1150 can impede aspanwise airflow occurring along the spanwise direction 1130 of thesecond wing 1106 when the second fence 1110 is in the deployed positionshown in FIG. 12. As another example, the panel 1150 can initiate and/orgenerate a vortex along the second wing 1106 when the second fence 1110is in the deployed position shown in FIG. 12.

The panel 1150 and/or, more generally, the second fence 1110 of FIGS. 11and 12 is rotatably coupled to the second wing 1106 of FIGS. 11 and 12via an example axle 1152 having an example central axis 1154. In theillustrated example of FIGS. 11 and 12, the central axis 1154 of theaxle 1152 is canted (e.g., oriented at an angle) relative to thechordwise direction 1136 of the second wing 1106. For example, as shownin FIGS. 11 and 12, the central axis 1154 of the axle 1152 is canted atan example toe-out angle 1156 relative to the chordwise direction 1136of the second wing 1106 such that a first end of the axle 1152positioned toward the leading edge 1138 of the second wing 1106 islocated further away from the longitudinal axis 1112 of the aircraft1100 than is a second end of the axle 1152 positioned toward thetrailing edge 1140 of the second wing 1106. The example toe-out angle1156 shown in FIGS. 11 and 12 is exaggerated for clarity. Whenimplemented, the toe-out angle 1156 preferably has a value ranging fromone to fifteen degrees.

The second fence 1110 of FIGS. 11 and 12 is configured to move from thedeployed position shown in FIG. 12 to the stowed position shown in FIG.11 in response to an aerodynamic force exerted on the panel 1150 of thesecond fence 1110. In some examples, the aerodynamic force may begenerated via a chordwise airflow (e.g., a cruise airflow) occurringalong the chordwise direction 1136 of the second wing 1106. In someexamples, an actuator operatively coupled to the second fence 1110biases and/or maintains the second fence 1110 in the deployed positionshown in FIG. 12 in response to the aerodynamic force exerted on thepanel 1150 of the second fence 1110 being less than a threshold forcevalue (e.g., less than the biasing force generated by the actuator).Example means for implementing the actuator are discussed below inconnection with FIGS. 13-20. In some disclosed examples, the secondfence 1110 moves from the deployed position shown in FIG. 12 to thestowed position shown in FIG. 11 in response to the aerodynamic forceexerted on the panel 1150 of the second fence 1110 being greater thanthe threshold force value (e.g., greater than the biasing forcegenerated by the actuator). In some disclosed examples, the second fence1110 is configured to move from the deployed position shown in FIG. 12to the stowed position shown in FIG. 11 during a cruise operation of theaircraft 1100 having a first speed, and the second fence 1110 is furtherconfigured to move from the stowed position shown in FIG. 11 to thedeployed position shown in FIG. 12 during a reduced speed operation(e.g., a takeoff or landing operation) of the aircraft 1100 having asecond speed less than the first speed.

FIGS. 13-20 provide additional views of the first example fence 1108 ofFIGS. 11 and 12 rotatably coupled to the first example wing 1104 ofFIGS. 11 and 12. More specifically, FIG. 13 is a cross-sectional view ofthe first example fence 1108 of FIGS. 11 and 12 looking inboard andtaken across the example central axis 1146 of the example axle 1144,with the first fence 1108 in the example stowed position of FIG. 11.FIG. 14 is a frontal view of the first example fence 1108 of FIGS. 11-13looking rearward along the example central axis 1146 of the example axle1144, with the first fence 1108 in the example stowed position of FIGS.11 and 13. FIG. 15 is a frontal view of the first example fence 1108 ofFIGS. 11-14 looking rearward along the example chordwise direction 1124of the first example wing 1104, with the first fence 1108 in the examplestowed position of FIGS. 11, 13 and 14. FIG. 16 is a plan view of thefirst example fence 1108 of FIGS. 11-15 in the example stowed positionof FIGS. 11 and 13-15. FIG. 17 is a cross-sectional view of the firstexample fence 1108 of FIGS. 11-16 looking inboard and taken across theexample central axis 1146 of the example axle 1144, with the first fence1108 in the example deployed position of FIG. 12. FIG. 18 is a frontalview of the first example fence 1108 of FIGS. 11-17 looking rearwardalong the example central axis 1146 of the example axle 1144, with thefirst fence 1108 in the example deployed position of FIGS. 12 and 17.FIG. 19 is a frontal view of the first example fence 1108 of FIGS. 11-18looking rearward along the example chordwise direction 1124 of the firstexample wing 1104, with the first fence 1108 in the example deployedposition of FIGS. 12, 17 and 18. FIG. 20 is a plan view of the firstexample fence 1108 of FIGS. 11-19 in the example deployed position ofFIGS. 12 and 17-19.

In the illustrated example of FIGS. 13-20, the first fence 1108 isrotatably coupled to the first wing 1104 via the axle 1144. The axle1144 includes a first example end 1302 coupled to the first wing 1104via a first example axle mount 1304, and further includes a secondexample end 1306 located opposite the first end 1302 and coupled to thefirst wing 1104 via a second example axle mount 1308. The first end 1302of the axle 1144 is positioned toward the leading edge 1126 of the firstwing 1104 and/or toward the first axle mount 1304, and the second end1306 of the axle 1144 is positioned toward the trailing edge 1128 of thefirst wing 1104 and/or toward the second axle mount 1308.

The first fence 1108 includes a first example end 1310, a second exampleend 1312 located opposite the first end 1310, and an example throughhole 1314 extending between the first end 1310 and the second end 1312of the first fence 1108. The first end 1310 of the first fence 1108 ispositioned toward the leading edge 1126 of the first wing 1104 and/ortoward the first axle mount 1304, and the second end 1312 of the firstfence 1108 is positioned toward the trailing edge 1128 of the first wing1104 and/or toward the second axle mount 1308. The axle 1144 passesand/or extends through the through hole 1314 of the first fence 1108such that the axle 1144 and the through hole 1314 are parallel and/orcoaxially located, and such that the first fence 1108 is secured to theaxle 1144 via the first axle mount 1304 and the second axle mount 1308.The first axle mount 1304 and the second axle mount 1308 accordinglysecure both the axle 1144 and the first fence 1108 to the first wing1104. The first fence 1108 is rotatable about the axle 1144, and is alsorotatable relative to the first wing 1104. For example, the first fence1108 is rotatable about the axle 1144 relative to the first wing 1104between the stowed position shown in FIGS. 11 and 13-16 and the deployedposition shown in FIGS. 12 and 17-20.

In the illustrated example of FIGS. 13-20, the panel 1142 of the firstfence 1108 extends in an outboard direction (e.g., away from thelongitudinal axis 1112 of the aircraft 1100) along the skin 1114 of thefirst wing 1104 when the first fence 1108 is in the stowed positionshown in FIGS. 13-16. As shown in FIGS. 13-16, the panel 1142 of thefirst fence 1108 extends along and is positioned over and/or on top ofthe skin 1114 of the first wing 1104 when the first fence 1108 is in thestowed position. In other examples, the panel 1142 of the first fence1108 can extend along and be recessed (e.g., fully or partiallyrecessed) relative to the skin 1114 of the first wing 1104 when thefirst fence 1108 is in the stowed position. As shown in FIGS. 17-20, thepanel 1142 of the first fence 1108 extends at an upward angle (e.g.,vertically) away from the skin 1114 of the first wing 1104 when thefirst fence 1108 is in the deployed position. The panel 1142 of thefirst fence 1108 is configured to impact the airflow around the aircraft1100 when the first fence 1108 is in the deployed position shown inFIGS. 17-20. For example, the panel 1142 can impede a spanwise airflowoccurring along the spanwise direction 1118 of the first wing 1104 whenthe first fence 1108 is in the deployed position shown in FIGS. 17-20.As another example, the panel 1142 can initiate and/or generate a vortexalong the first wing 1104 when the first fence 1108 is in the deployedposition shown in FIGS. 17-20.

In the illustrated example of FIGS. 13-20, the panel 1142 of the firstfence 1108 is planar. In other examples, the panel 1142 of the firstfence 1108 can be non-planar. For example, the panel 1142 of the firstfence 1108 can have a non-planar (e.g., curved) aerodynamic shape. Insome examples, the non-planar aerodynamic shape can be configured tomatch and/or mimic a non-planar (e.g., curved) aerodynamic shape of thefirst wing 1104. In the illustrated example of FIGS. 13-20, the panel1142 of the first fence 1108 has a trapezoidal shape between the firstend 1310 of the first fence 1108 and the second end 1312 of the firstfence 1108. In other examples, the panel 1142 of the first fence 1108can have a different (e.g., non-trapezoidal) shape between the first end1310 of the first fence 1108 and the second end 1312 of the first fence1108. For example, the panel 1142 of the first fence 1108 can have anyof a rectangular shape, a square shape, a triangular shape, asemicircular shape, a circular shape, or an elliptical shape, amongothers, between the first end 1310 of the first fence 1108 and thesecond end 1312 of the first fence 1108.

In the illustrated example of FIGS. 13-20, an example spring-loaded axle1316 is formed via the axle 1144 and an example spring 1318 coiledaround a portion of the axle 1144. As further described below, thespring 1318 and/or, more generally, the spring-loaded axle 1316function(s) and/or operate(s) as an actuator configured to move thefirst fence 1108 between the stowed position shown in FIGS. 13-16 andthe deployed position shown in FIGS. 17-20, dependent upon the directionand/or strength of airflows caught by and/or received at the panel 1142of the first fence 1108. In the illustrated example of FIGS. 13-20, thespring 1318 of the spring-loaded axle 1316 is located between the secondend 1312 of the first fence 1108 and the second axle mount 1308. Thespring 1318 and/or, more generally, the spring-loaded axle 1316 is/areoperatively coupled to the first fence 1108 such that the spring 1318and/or the spring-loaded axle 1316 bias(es) the first fence 1108 to thedeployed position shown in FIGS. 17-20. For example, the spring 1318 ofthe spring-loaded axle 1316 generates a restoring force (e.g., a biasingforce) having a restoring force value. In the absence of a deflectingforce (e.g., a counter-biasing force, as may be generated via achordwise and/or cruise airflow) opposing the restoring force and havinga deflecting force value that is greater than the restoring force value,the restoring force generated via the spring 1318 moves (e.g., rotates)the first fence 1108 to, and/or maintains the first fence 1108 in, thedeployed position shown in FIGS. 17-20.

In the illustrated example of FIGS. 13-20, the spring 1318 is in arelatively more wound state when the first fence 1108 is in the stowedposition shown in FIGS. 13-16 compared to when the first fence 1108 isin the deployed position shown in FIGS. 17-20. Conversely, the spring1318 is in a relatively more unwound state when the first fence 1108 isin the deployed position shown in FIGS. 17-20 compared to when the firstfence 1108 is in the stowed position shown in FIGS. 13-16. Stateddifferently, the spring 1318 winds around the spring-loaded axle 1316 asthe first fence 1108 moves from the deployed position shown in FIGS.17-20 to the stowed position shown in FIGS. 13-16, and the spring 1318conversely unwinds around the spring-loaded axle 1316 as the first fence1108 moves from the stowed position shown in FIGS. 13-16 to the deployedposition shown in FIGS. 17-20. In the illustrated example of FIGS.13-20, the spring 1318 is implemented via one or more torsion spring(s).In other examples, the spring 1318 may additionally or alternatively beimplemented via one or more (e.g., individually or in combination)suitably arranged leaf spring(s), compression spring(s), and/or tensionspring(s).

Movement (e.g., rotation) of the first fence 1108 relative to the firstwing 1104 is airflow dependent. For example, as described above inconnection with FIGS. 11 and 12 and further shown in FIGS. 13-20, thecentral axis 1146 of the axle 1144 is canted at the toe-out angle 1148relative to the chordwise direction 1124 of the first wing 1104.Positioning and/or orienting the central axis 1146 of the axle 1144 atthe toe-out angle 1148 causes the panel 1142 of the first fence 1108 tobe positioned and/or oriented in a similar manner. When the first fence1108 is in the deployed position shown in FIGS. 17-20 (e.g., as may becaused by the restoring force generated by the spring 1318 of thespring-loaded axle 1316), the panel 1142 of the first fence 1108 ispositioned to catch, receive and/or react to a chordwise airflow (e.g.,a cruise airflow) occurring along the chordwise direction 1124 of thefirst wing 1104. As a result of the toe-out angle 1148 at which thecentral axis 1146 of the axle 1144 is canted, the chordwise airflowoccurring along the chordwise direction 1124 of the first wing 1104carries a deflecting force component that counteracts (e.g., opposes)the restoring force generated by the spring 1318 of the spring-loadedaxle 1316.

If the deflecting force component of the chordwise airflow received at,applied to, and/or exerted on the panel 1142 of the first fence 1108 isgreater than the restoring force generated by the spring 1318 of thespring-loaded axle 1316, the chordwise airflow moves the first fence1108 from the deployed position shown in FIGS. 17-20 to the stowedposition shown in FIGS. 13-16. If the deflecting force component of thechordwise airflow received at, applied to, and/or exerted on the panel1142 of the first fence 1108 is instead less than the restoring forcegenerated by the spring 1318 of the spring-loaded axle 1316, the spring1318 maintains the first fence 1108 in the deployed position shown inFIGS. 17-20, and/or moves the first fence 1108 from the stowed positionshown in FIGS. 13-16 to the deployed position shown in FIGS. 17-20.Movement of the first fence 1108 relative to the first wing 1104 isaccordingly dependent on the presence or absence of the chordwiseairflow, and on the relative strength (e.g., force) of such airflow.

In some examples, the first fence 1108 is configured to move from thedeployed position shown in FIGS. 17-20 to the stowed position shown inFIGS. 13-16 during a cruise operation of the aircraft 1100 having afirst speed, and the first fence 1108 is further configured to move fromthe stowed position of FIGS. 13-16 to the deployed position of FIGS.17-20 during a reduced speed operation (e.g., a takeoff or landingoperation) of the aircraft 1100 having a second speed less than thefirst speed. For example, the spring 1318 of the spring-loaded axle 1316may be configured and/or implemented to have a spring constant thatcauses the spring 1318 to generate a restoring force sufficient to movethe first fence 1108 to, and/or sufficient to maintain the first fence1108 in, the deployed position shown in FIGS. 17-20 when the aircraft1100 is traveling at a speed less than a speed threshold (e.g., lessthan a cruise speed). When the aircraft 1100 is traveling at a speedabove or equal to the speed threshold, the restoring force generated bythe spring 1318 of the spring-loaded axle 1316 is overcome via adeflecting force, and the first fence 1108 accordingly moves from thedeployed position shown in FIGS. 17-20 to the stowed position shown inFIGS. 13-16.

While FIGS. 13-20 and the descriptions thereof provided above aredirected to the actuator of the first fence 1108 being implemented as aspring-loaded axle (e.g., spring-loaded axle 1316) configured to biasand/or move the first fence 1108 from the stowed position shown in FIGS.13-16 to the deployed position shown in FIGS. 17-20, the actuator of thefirst fence 1108 can be implemented in other forms including, forexample, electrical, hydraulic, pneumatic, motor-driven, and/or shapememory alloy actuators. Furthermore, while FIGS. 13-20 and thedescriptions thereof provided above are directed to the first fence 1108of FIGS. 11 and 12 that is rotatably coupled to the first wing 1104 ofFIGS. 11 and 12, the informed reader will recognize that the secondfence 1110 of FIGS. 11 and 12 that is rotatably coupled to the secondwing 1106 of FIGS. 11 and 12 can be similarly implemented (e.g., in amanner that is mirrored about the longitudinal axis 1112 of the aircraft1100). Moreover, while FIGS. 13-20 and the descriptions thereof providedabove are directed to the first fence 1108 of FIGS. 11 and 12 that isrotatably coupled to the first wing 1104 of FIGS. 11 and 12, theinformed reader will recognize that any number of additional fences canbe similarly implemented on the first wing 1104.

FIG. 21 illustrates another example aircraft 2100 in which exampleairflow-dependent deployable fences can be implemented in accordancewith teachings of this disclosure. FIG. 21 illustrates the exampleaircraft 2100 of FIG. 21 with the example airflow-dependent deployablefences of FIG. 21 stowed. FIG. 22 illustrates the example aircraft 2100of FIG. 21 with the example airflow-dependent deployable fences of FIG.21 deployed. The aircraft 2200 can be any form and/or type of aircraftincluding, for example, a civil (e.g., business or commercial) aircraft,a military aircraft, a manned (e.g., piloted) aircraft, an unmannedaircraft (e.g., a drone), etc. In the illustrated example of FIGS. 21and 22, the aircraft 2100 includes an example fuselage 2102, a firstexample wing 2104 (e.g., a left-side wing), a second example wing 2106(e.g., a right-side wing), a first example fence 2108 (e.g., a left-sidefence), and a second example fence 2110 (e.g., a right-side fence).Although the illustrated example of FIGS. 21 and 22 depicts only asingle fence located on each wing of the aircraft 2100 (e.g., the firstfence 2108 located on the first wing 2104, and the second fence 2110located on the second wing 2106), other example implementations caninclude multiple (e.g., 2, 3, 4, etc.) fences located on each wing ofthe aircraft 2100. In some examples, the location(s), size(s), and/orshape(s) of respective ones of the fences (e.g., the first fence 2108and the second fence 2110) of the aircraft 2100 can differ relative tothe location(s), size(s) and/or shape(s) of the fences shown in FIGS. 21and 22.

The fuselage 2102 of FIGS. 21 and 22 has a generally cylindrical shapethat defines an example longitudinal axis 2112 of the aircraft 2100. Thefirst wing 2104 and the second wing 2106 of FIGS. 21 and 22 arerespectively coupled to the fuselage 2102 and swept in a rearwarddirection of the aircraft 2100. The first wing 2104 includes an exampleskin 2114 forming (e.g., forming all or part of) an outer surface of thefirst wing 2104, and the second wing 2106 includes an example skin 2116forming (e.g., forming all or part of) an outer surface of the secondwing 2106.

The first wing 2104 of FIGS. 21 and 22 defines an example spanwisedirection 2118 moving from an example inboard portion 2120 (e.g.,inboard relative to the spanwise location of the first fence 2108) ofthe first wing 2104 toward an example outboard portion 2122 (e.g.,outboard relative to the spanwise location of the first fence 2108) ofthe first wing 2104. The spanwise direction 2118 defined by the firstwing 2104 is representative of a direction of a spanwise airflow thatmay occur along the first wing 2104. The first wing 2104 also defines anexample chordwise direction 2124 moving from an example leading edge2126 of the first wing 2104 toward an example trailing edge 2128 of thefirst wing 2104. The chordwise direction 2124 defined by the first wing2104 is representative of a direction of a cruise airflow that may occuralong the first wing 2104.

The second wing 2106 of FIGS. 21 and 22 defines an example spanwisedirection 2130 moving from an example inboard portion 2132 (e.g.,inboard relative to the spanwise location of the second fence 2110) ofthe second wing 2106 toward an example outboard portion 2134 (e.g.,outboard relative to the spanwise location of the second fence 2110) ofthe second wing 2106. The spanwise direction 2130 defined by the secondwing 2106 is representative of a direction of a spanwise airflow thatmay occur along the second wing 2106. The second wing 2106 also definesan example chordwise direction 2136 moving from an example leading edge2138 of the second wing 2106 toward an example trailing edge 2140 of thesecond wing 2106. The chordwise direction 2136 defined by the secondwing 2106 is representative of a direction of a cruise airflow that mayoccur along the second wing 2106.

The first fence 2108 of FIGS. 21 and 22 is rotatably coupled to thefirst wing 2104 such that the first fence 2108 is movable (e.g.,rotatable) between the stowed position shown in FIG. 21 and the deployedposition shown in FIG. 22. The first fence 2108 includes an examplepanel 2142. The panel 2142 of the first fence 2108 extends (e.g., in aninboard direction toward the longitudinal axis 2112) along the skin 2114of the first wing 2104 when the first fence 2108 is in the stowedposition shown in FIG. 21. In some examples, the panel 2142 of the firstfence 2108 extends along and is positioned over and/or on top of theskin 2114 of the first wing 2104 when the first fence 2108 is in thestowed position shown in FIG. 21. In other examples, the panel 2142 ofthe first fence 2108 extends along and is recessed (e.g., fully orpartially recessed) relative to the skin 2114 of the first wing 2104when the first fence 2108 is in the stowed position shown in FIG. 21.The panel 2142 of the first fence 2108 extends at an upward angle (e.g.,vertically) away from the skin 2114 of the first wing 2104 when thefirst fence 2108 is in the deployed position shown in FIG. 22. The panel2142 of the first fence 2108 is configured to impact the airflow aroundthe aircraft 2100 when the first fence 2108 is in the deployed positionshown in FIG. 22. For example, the panel 2142 can impede a spanwiseairflow occurring along the spanwise direction 2118 of the first wing2104 when the first fence 2108 is in the deployed position shown in FIG.22. As another example, the panel 2142 can initiate and/or generate avortex along the first wing 2104 when the first fence 2108 is in thedeployed position shown in FIG. 22.

The first fence 2108 further includes an example deployment vane 2144.In the illustrated example of FIGS. 21 and 22, the deployment vane 2144of the first fence 2108 is orthogonal to the panel 2142 of the firstfence 2108. In other examples, the deployment vane 2144 of the firstfence 2108 can be oriented at a non-orthogonal angle relative to thepanel 2142 of the first fence 2108. For example, the deployment vane2144 of the first fence 2108 can be oriented at an angle betweenforty-five and one hundred thirty-five degrees relative to the panel2142 of the first fence 2108. The deployment vane 2144 of the firstfence 2108 extends (e.g., in an outboard direction away from thelongitudinal axis 2112) along the skin 2114 of the first wing 2104 whenthe first fence 2108 is in the deployed position shown in FIG. 22. Insome examples, the deployment vane 2144 of the first fence 2108 extendsalong and is positioned over and/or on top of the skin 2114 of the firstwing 2104 when the first fence 2108 is in the deployed position shown inFIG. 22. In other examples, the deployment vane 2144 of the first fence2108 extends along and is recessed (e.g., fully or partially recessed)relative to the skin 2114 of the first wing 2104 when the first fence2108 is in the deployed position shown in FIG. 22. The deployment vane2144 of the first fence 2108 extends at an upward angle (e.g.,vertically) away from the skin 2114 of the first wing 2104 when thefirst fence 2108 is in the stowed position shown in FIG. 21. Thedeployment vane 2144 of the first fence 2108 is configured to catch,receive and/or react to a spanwise airflow occurring along the spanwisedirection 2118 of the first wing 2104 when the first fence 2108 is inthe stowed position shown in FIG. 21.

The panel 2142 and the deployment vane 2144, and/or, more generally, thefirst fence 2108 of FIGS. 21 and 22 is/are rotatably coupled to thefirst wing 2104 of FIGS. 21 and 22 via an example axle 2146 having anexample central axis 2148. In the illustrated example of FIGS. 21 and22, the central axis 2148 of the axle 2146 is parallel to the chordwisedirection 2124 of the first wing 2104. In other examples, the centralaxis 2148 of the axle 2146 can be canted (e.g., at a toe-in angle or atoe-out angle) relative to the chordwise direction 2124 of the firstwing 2104. The first fence 2108 of FIGS. 21 and 22 is configured to movefrom the stowed position shown in FIG. 21 to the deployed position shownin FIG. 22 in response to an aerodynamic force exerted on the deploymentvane 2144 of the first fence 2108. In some examples, the aerodynamicforce may be generated via a spanwise airflow occurring along thespanwise direction 2118 of the first wing 2104. In some disclosedexamples, an actuator operatively coupled to the first fence 2108 biasesand/or maintains the first fence 2108 in the stowed position shown inFIG. 21 in response to the aerodynamic force exerted on the deploymentvane 2144 of the first fence 2108 being less than a threshold forcevalue (e.g., less than the biasing force generated by the actuator).Example means for implementing the actuator are discussed below inconnection with FIGS. 23-28. In some disclosed examples, the first fence2108 moves from the stowed position shown in FIG. 21 to the deployedposition shown in FIG. 22 in response to the aerodynamic force exertedon the deployment vane 2144 of the first fence 2108 being greater thanthe threshold force value (e.g., greater than the biasing forcegenerated by the actuator).

The second fence 2110 of FIGS. 21 and 22 is rotatably coupled to thesecond wing 2106 such that the second fence 2110 is movable (e.g.,rotatable) between the stowed position shown in FIG. 21 and the deployedposition shown in FIG. 22. The second fence 2110 includes an examplepanel 2150. The panel 2150 of the second fence 2110 extends (e.g., in aninboard direction toward the longitudinal axis 2112) along the skin 2116of the second wing 2106 when the second fence 2110 is in the stowedposition shown in FIG. 21. In some examples, the panel 2150 of thesecond fence 2110 extends along and is positioned over and/or on top ofthe skin 2116 of the second wing 2106 when the second fence 2110 is inthe stowed position shown in FIG. 21. In other examples, the panel 2150of the second fence 2110 extends along and is recessed (e.g., fully orpartially recessed) relative to the skin 2116 of the second wing 2106when the second fence 2110 is in the stowed position shown in FIG. 21.The panel 2150 of the second fence 2110 extends at an upward angle(e.g., vertically) away from the skin 2116 of the second wing 2106 whenthe second fence 2110 is in the deployed position shown in FIG. 22. Thepanel 2150 of the second fence 2110 is configured to impact the airflowaround the aircraft 2100 when the second fence 2110 is in the deployedposition shown in FIG. 22. For example, the panel 2150 can impede aspanwise airflow occurring along the spanwise direction 2130 of thesecond wing 2106 when the second fence 2110 is in the deployed positionshown in FIG. 22. As another example, the panel 2150 can initiate and/orgenerate a vortex along the second wing 2106 when the second fence 2110is in the deployed position shown in FIG. 22.

The second fence 2110 further includes an example deployment vane 2152.In the illustrated example of FIGS. 21 and 22, the deployment vane 2152of the second fence 2110 is orthogonal to the panel 2150 of the secondfence 2110. In other examples, the deployment vane 2152 of the secondfence 2110 can be oriented at a non-orthogonal angle relative to thepanel 2150 of the second fence 2110. For example, the deployment vane2152 of the second fence 2110 can be oriented at an angle betweenforty-five and one hundred thirty-five degrees relative to the panel2150 of the second fence 2110. The deployment vane 2152 of the secondfence 2110 extends (e.g., in an outboard direction away from thelongitudinal axis 2112) along the skin 2116 of the second wing 2106 whenthe second fence 2110 is in the deployed position shown in FIG. 22. Insome examples, the deployment vane 2152 of the second fence 2110 extendsalong and is positioned over and/or on top of the skin 2116 of thesecond wing 2106 when the second fence 2110 is in the deployed positionshown in FIG. 22. In other examples, the deployment vane 2152 of thesecond fence 2110 extends along and is recessed (e.g., fully orpartially recessed) relative to the skin 2116 of the second wing 2106when the second fence 2110 is in the deployed position shown in FIG. 22.The deployment vane 2152 of the second fence 2110 extends at an upwardangle (e.g., vertically) away from the skin 2116 of the second wing 2106when the second fence 2110 is in the stowed position shown in FIG. 21.The deployment vane 2152 of the second fence 2110 is configured tocatch, receive and/or react to a spanwise airflow occurring along thespanwise direction 2130 of the second wing 2106 when the second fence2110 is in the stowed position shown in FIG. 21.

The panel 2150 and the deployment vane 2152, and/or, more generally, thesecond fence 2110 of FIGS. 21 and 22 is/are rotatably coupled to thesecond wing 2106 of FIGS. 21 and 22 via an example axle 2154 having anexample central axis 2156. In the illustrated example of FIGS. 21 and22, the central axis 2156 of the axle 2154 is parallel to the chordwisedirection 2136 of the second wing 2106. In other examples, the centralaxis 2156 of the axle 2154 can be canted (e.g., at a toe-in angle or atoe-out angle) relative to the chordwise direction 2136 of the secondwing 2106. The second fence 2110 of FIGS. 21 and 22 is configured tomove from the stowed position shown in FIG. 21 to the deployed positionshown in FIG. 22 in response to an aerodynamic force exerted on thedeployment vane 2152 of the second fence 2110. In some examples, theaerodynamic force may be generated via a spanwise airflow occurringalong the spanwise direction 2130 of the second wing 2106. In somedisclosed examples, an actuator operatively coupled to the second fence2110 biases and/or maintains the second fence 2110 in the stowedposition shown in FIG. 21 in response to the aerodynamic force exertedon the deployment vane 2152 of the second fence 2110 being less than athreshold force value (e.g., less than the biasing force generated bythe actuator). Example means for implementing the actuator are discussedbelow in connection with FIGS. 23-28. In some disclosed examples, thesecond fence 2110 moves from the stowed position shown in FIG. 11 to thedeployed position shown in FIG. 22 in response to the aerodynamic forceexerted on the deployment vane 2152 of the second fence 2110 beinggreater than the threshold force value (e.g., greater than the biasingforce generated by the actuator).

FIGS. 23-28 provide additional views of the first example fence 2108 ofFIGS. 21 and 22 rotatably coupled to the first example wing 2104 ofFIGS. 21 and 22. More specifically, FIG. 23 is a cross-sectional view ofthe first example fence 2108 of FIGS. 21 and 22 looking inboard andtaken across the example central axis 2148 of the example axle 2146,with the first fence 2108 in the example stowed position of FIG. 21.FIG. 14 is a frontal view of the first example fence 2108 of FIGS. 21-23looking rearward along the example central axis 2148 of the example axle2146, with the first fence 2108 in the example stowed position of FIGS.21 and 23. FIG. 25 is a plan view of the first example fence 2108 ofFIGS. 21-24 in the example stowed position of FIGS. 21, 23 and 24. FIG.26 is a cross-sectional view of the first example fence 2108 of FIGS.21-25 looking inboard and taken across the example central axis 2148 ofthe example axle 2146, with the first fence 2108 in the example deployedposition of FIG. 22. FIG. 27 is a frontal view of the first examplefence 2108 of FIGS. 21-26 looking rearward along the example centralaxis 2148 of the example axle 2146, with the first fence 2108 in theexample deployed position of FIGS. 22 and 26. FIG. 28 is a plan view ofthe first example fence 2108 of FIGS. 21-27 in the example deployedposition of FIGS. 22, 26 and 27.

In the illustrated example of FIGS. 23-28, the first fence 2108 isrotatably coupled to the first wing 2104 via the axle 2146. The axle2146 includes a first example end 2302 coupled to the first wing 2104via a first example axle mount 2304, and further includes a secondexample end 2306 located opposite the first end 2302 and coupled to thefirst wing 2104 via a second example axle mount 2308. The first end 2302of the axle 2146 is positioned toward the leading edge 2126 of the firstwing 2104 and/or toward the first axle mount 2304, and the second end2306 of the axle 2146 is positioned toward the trailing edge 2128 of thefirst wing 2104 and/or toward the second axle mount 2308.

The first fence 2108 includes a first example end 2310, a second exampleend 2312 located opposite the first end 2310, and an example throughhole 2314 extending between the first end 2310 and the second end 2312of the first fence 2108. The first end 2310 of the first fence 2108 ispositioned toward the leading edge 2126 of the first wing 2104 and/ortoward the first axle mount 2304, and the second end 2312 of the firstfence 2108 is positioned toward the trailing edge 2128 of the first wing2104 and/or toward the second axle mount 2308. The axle 2146 passesand/or extends through the through hole 2314 of the first fence 2108such that the axle 2146 and the through hole 2314 are parallel and/orcoaxially located, and such that the first fence 2108 is secured to theaxle 2146 via the first axle mount 2304 and the second axle mount 2308.The first axle mount 2304 and the second axle mount 2308 accordinglysecure both the axle 2146 and the first fence 2108 to the first wing2104. The first fence 2108 is rotatable about the axle 2146, and is alsorotatable relative to the first wing 2104. For example, the first fence2108 is rotatable about the axle 2146 relative to the first wing 2104between the stowed position shown in FIGS. 21 and 23-25 and the deployedposition shown in FIGS. 22 and 26-28.

In the illustrated example of FIGS. 23-28, the panel 2142 of the firstfence 2108 extends in an inboard direction (e.g., toward thelongitudinal axis 2112 of the aircraft 2100) along the skin 2114 of thefirst wing 2104 when the first fence 2108 is in the stowed positionshown in FIGS. 23-25. As shown in FIGS. 23-25, the panel 2142 of thefirst fence 2108 extends along and is positioned over and/or on top ofthe skin 2114 of the first wing 2104 when the first fence 2108 is in thestowed position. In other examples, the panel 2142 of the first fence2108 can extend along and be recessed (e.g., fully or partiallyrecessed) relative to the skin 2114 of the first wing 2104 when thefirst fence 2108 is in the stowed position. As shown in FIGS. 26-28, thepanel 2142 of the first fence 2108 extends at an upward angle (e.g.,vertically) away from the skin 2114 of the first wing 2104 when thefirst fence 2108 is in the deployed position. The panel 2142 of thefirst fence 2108 is configured to impact the airflow around the aircraft2100 when the first fence 2108 is in the deployed position shown inFIGS. 26-28. For example, the panel 2142 can impede a spanwise airflowoccurring along the spanwise direction 2118 of the first wing 2104 whenthe first fence 2108 is in the deployed position shown in FIGS. 26-28.As another example, the panel 2142 can initiate and/or generate a vortexalong the first wing 2104 when the first fence 2108 is in the deployedposition shown in FIGS. 26-28.

In the illustrated example of FIGS. 23-28, the panel 2142 of the firstfence 2108 is planar. In other examples, the panel 2142 of the firstfence 2108 can be non-planar. For example, the panel 2142 of the firstfence 2108 can have a non-planar (e.g., curved) aerodynamic shape. Insome examples, the non-planar aerodynamic shape can be configured tomatch and/or mimic a non-planar (e.g., curved) aerodynamic shape of thefirst wing 2104. In the illustrated example of FIGS. 23-28, the panel2142 of the first fence 2108 has a trapezoidal shape between the firstend 2310 of the first fence 2108 and the second end 2312 of the firstfence 2108. In other examples, the panel 2142 of the first fence 2108can have a different (e.g., non-trapezoidal) shape between the first end2310 of the first fence 2108 and the second end 2312 of the first fence2108. For example, the panel 2142 of the first fence 2108 can have anyof a rectangular shape, a square shape, a triangular shape, asemicircular shape, a circular shape, or an elliptical shape, amongothers, between the first end 2310 of the first fence 2108 and thesecond end 2312 of the first fence 2108.

In the illustrated example of FIGS. 23-28, the deployment vane 2144 ofthe first fence 2108 extends in an outboard direction (e.g., away fromthe longitudinal axis 2112 of the aircraft 2100) along the skin 2114 ofthe first wing 2104 when the first fence 2108 is in the deployedposition shown in FIGS. 26-28. As shown in FIGS. 26-28, the deploymentvane 2144 of the first fence 2108 extends along and is positioned overand/or on top of the skin 2114 of the first wing 2104 when the firstfence 2108 is in the deployed position. In other examples, thedeployment vane 2144 of the first fence 2108 can extend along and berecessed (e.g., fully or partially recessed) relative to the skin 2114of the first wing 2104 when the first fence 2108 is in the deployedposition. As shown in FIGS. 23-25, the deployment vane 2144 of the firstfence 2108 extends at an upward angle (e.g., vertically) away from theskin 2114 of the first wing 2104 when the first fence 2108 is in thestowed position. The deployment vane 2144 of the first fence 2108 isconfigured to catch, receive, and/or react to a spanwise airflow thatmay occur along the spanwise direction 2118 of the first wing 2104 whenthe first fence 2108 is in the stowed position shown in FIGS. 23-25.

In the illustrated example of FIGS. 23-28, the deployment vane 2144 ofthe first fence 2108 is planar. In other examples, the deployment vane2144 of the first fence 2108 can be non-planar. For example, thedeployment vane 2144 of the first fence 2108 can have a non-planar(e.g., curved) aerodynamic shape. In some examples, the non-planaraerodynamic shape can be configured to match and/or mimic a non-planar(e.g., curved) aerodynamic shape of the first wing 2104. In theillustrated example of FIGS. 23-28, the deployment vane 2144 of thefirst fence 2108 has a trapezoidal shape between the first end 2310 ofthe first fence 2108 and the second end 2312 of the first fence 2108. Inother examples, the deployment vane 2144 of the first fence 2108 canhave a different (e.g., non-trapezoidal) shape between the first end2310 of the first fence 2108 and the second end 2312 of the first fence2108. For example, the deployment vane 2144 of the first fence 2108 canhave any of a rectangular shape, a square shape, a triangular shape, asemicircular shape, a circular shape, or an elliptical shape, amongothers, between the first end 2310 of the first fence 2108 and thesecond end 2312 of the first fence 2108. In the illustrated example ofFIGS. 23-28, the size of the deployment vane 2144 of the first fence2108 is smaller than the size of the panel 2142 of the first fence 2108.In other examples, the deployment vane 2144 of the first fence 2108 canhave a size that is less than or equal to the size of the panel 2142 ofthe first fence 2108.

In the illustrated example of FIGS. 23-28, an example spring-loaded axle2316 is formed via the axle 2146 and an example spring 2318 coiledaround a portion of the axle 2146. As further described below, thespring 2318 and/or, more generally, the spring-loaded axle 2316function(s) and/or operate(s) as an actuator configured to move thefirst fence 2108 between the stowed position shown in FIGS. 23-25 andthe deployed position shown in FIGS. 26-28, dependent upon the directionand/or strength of airflows caught by and/or received at the deploymentvane 2144 of the first fence 2108. In the illustrated example of FIGS.23-28, the spring 2318 of the spring-loaded axle 2316 is located betweenthe second end 2312 of the first fence 2108 and the second axle mount2308. The spring 2318 and/or, more generally, the spring-loaded axle2316 is/are operatively coupled to the first fence 2108 such that thespring 2318 and/or the spring-loaded axle 2316 bias(es) the first fence2108 to the stowed position shown in FIGS. 23-25. For example, thespring 2318 of the spring-loaded axle 2316 generates a restoring force(e.g., a biasing force) having a restoring force value. In the absenceof a deflecting force (e.g., a counter-biasing force, as may begenerated via a spanwise airflow) opposing the restoring force andhaving a deflecting force value that is greater than the restoring forcevalue, the restoring force generated via the spring 2318 moves (e.g.,rotates) the first fence 2108 to, and/or maintains the first fence 2108in, the stowed position shown in FIGS. 23-25.

In the illustrated example of FIGS. 23-28, the spring 2318 is in arelatively more wound state when the first fence 2108 is in the deployedposition shown in FIGS. 26-28 compared to when the first fence 2108 isin the stowed position shown in FIGS. 23-25. Conversely, the spring 2318is in a relatively more unwound state when the first fence 2108 is inthe stowed position shown in FIGS. 23-25 compared to when the firstfence 2108 is in the deployed position shown in FIGS. 26-28. Stateddifferently, the spring 2318 winds around the spring-loaded axle 2316 asthe first fence 2108 moves from the stowed position shown in FIGS. 23-25to the deployed position shown in FIGS. 26-28, and the spring 2318conversely unwinds around the spring-loaded axle 2316 as the first fence2108 moves from the deployed position shown in FIGS. 26-28 to the stowedposition shown in FIGS. 23-25. In the illustrated example of FIGS.23-28, the spring 2318 is implemented via one or more torsion spring(s).In other examples, the spring 2318 may additionally or alternatively beimplemented via one or more (e.g., individually or in combination)suitably arranged leaf spring(s), compression spring(s), and/or tensionspring(s).

Movement (e.g., rotation) of the first fence 2108 relative to the firstwing 2104 is airflow dependent. For example, as described above inconnection with FIGS. 21 and 22 and further shown in FIGS. 23-28, thecentral axis 2148 of the axle 2146 is parallel to the chordwisedirection 2124 of the first wing 2104. Positioning and/or orienting thecentral axis 2148 of the axle 2146 in this manner causes the panel 2142and the deployment vane 2144 of the first fence 2108 to be positionedand/or oriented in a similar manner. The deployment vane 2144 of thefirst fence 2108 is orthogonal relative to the panel 2142 of the firstfence 2108. When the first fence 2108 is in the stowed position shown inFIGS. 23-25 (e.g., as may be caused by the restoring force generated bythe spring 2318 of the spring-loaded axle 2316), the deployment vane2144 of the first fence 2108 is positioned to catch, receive and/orreact to a spanwise airflow occurring along the spanwise direction 2118of the first wing 2104. The spanwise airflow occurring along thespanwise direction 2118 of the first wing 2104 carries a deflectingforce component that counteracts (e.g., opposes) the restoring forcegenerated by the spring 2318 of the spring-loaded axle 2316.

If the deflecting force component of the spanwise airflow received at,applied to, and/or exerted on the deployment vane 2144 of the firstfence 2108 is greater than the restoring force generated by the spring2318 of the spring-loaded axle 2316, the spanwise airflow moves thefirst fence 2108 from the stowed position shown in FIGS. 23-25 to thedeployed position shown in FIGS. 26-28. If the deflecting forcecomponent of the spanwise airflow received at, applied to, and/orexerted on the deployment vane 2144 of the first fence 2108 is insteadless than the restoring force generated by the spring 2318 of thespring-loaded axle 2316, the spring 2318 maintains the first fence 2108in the stowed position shown in FIGS. 23-25, and/or moves the firstfence 2108 from the deployed position shown in FIGS. 26-28 to the stowedposition shown in FIGS. 23-25. Movement of the first fence 2108 relativeto the first wing 2104 is accordingly dependent on the presence orabsence of the spanwise airflow, and on the relative strength (e.g.,force) of such airflow.

While FIGS. 23-28 and the descriptions thereof provided above aredirected to the actuator of the first fence 2108 being implemented as aspring-loaded axle (e.g., spring-loaded axle 2316) configured to biasand/or move the first fence 2108 from the deployed position shown inFIGS. 26-28 to the stowed position shown in FIGS. 23-25, the actuator ofthe first fence 2108 can be implemented in other forms including, forexample, electrical, hydraulic, pneumatic, motor-driven, and/or shapememory alloy actuators. Furthermore, while FIGS. 23-28 and thedescriptions thereof provided above are directed to the first fence 2108of FIGS. 21 and 22 that is rotatably coupled to the first wing 2104 ofFIGS. 21 and 22, the informed reader will recognize that the secondfence 2110 of FIGS. 21 and 22 that is rotatably coupled to the secondwing 2106 of FIGS. 21 and 22 can be similarly implemented (e.g., in amanner that is mirrored about the longitudinal axis 2112 of the aircraft2100). Moreover, while FIGS. 23-28 and the descriptions thereof providedabove are directed to the first fence 2108 of FIGS. 21 and 22 that isrotatably coupled to the first wing 2104 of FIGS. 21 and 22, theinformed reader will recognize that any number of additional fences canbe similarly implemented on the first wing 2104.

In some examples, two or more of the above-described components (e.g.,the first fence 108, the axle 144, the first axle mount 304, the secondaxle mount 308, and/or the spring 318 of FIGS. 1-10, the first fence1108, the axle 1144, the first axle mount 1304, the second axle mount1308, and/or the spring 1318 of FIGS. 11-20, the first fence 2108, theaxle 2146, the first axle mount 2304, the second axle mount 2308, and/orthe spring 2318 of FIGS. 21-28, etc.) may be manufactured or fabricatedas a single piece, formed of an elastic material such as a carbon fibercomposite or a 3D-printed plastic, and structured or configured tocreate an elastic restoring force. For example, FIG. 29 illustratesanother example aircraft 2900 in which example airflow-dependentdeployable fences can be implemented in accordance with teachings ofthis disclosure. FIG. 29 illustrates the example aircraft 2900 of FIG.29 with the example airflow-dependent deployable fences of FIG. 29stowed. FIG. 30 illustrates the example aircraft 2900 of FIG. 29 withthe example airflow-dependent deployable fences of FIG. 29 deployed. Theaircraft 2900 can be any form and/or type of aircraft including, forexample, a civil (e.g., business or commercial) aircraft, a militaryaircraft, a manned (e.g., piloted) aircraft, an unmanned aircraft (e.g.,a drone), etc. In the illustrated example of FIGS. 29 and 30, theaircraft 2900 includes an example fuselage 2902, a first example wing2904 (e.g., a left-side wing), a second example wing 2906 (e.g., aright-side wing), a first example fence 2908 (e.g., a left-side fence),and a second example fence 2910 (e.g., a right-side fence). Although theillustrated example of FIGS. 29 and 30 depicts only a single fencelocated on each wing of the aircraft 2900 (e.g., the first fence 2908located on the first wing 2904, and the second fence 2910 located on thesecond wing 2906), other example implementations can include multiple(e.g., 2, 3, 4, etc.) fences located on each wing of the aircraft 2900.In some examples, the location(s), size(s), and/or shape(s) ofrespective ones of the fences (e.g., the first fence 2908 and the secondfence 2910) of the aircraft 2900 can differ relative to the location(s),size(s) and/or shape(s) of the fences shown in FIGS. 29 and 30.

The fuselage 2902 of FIGS. 29 and 30 has a generally cylindrical shapethat defines an example longitudinal axis 2912 of the aircraft 2900. Thefirst wing 2904 and the second wing 2906 of FIGS. 29 and 30 arerespectively coupled to the fuselage 2902 and swept in a rearwarddirection of the aircraft 2900. The first wing 2904 includes an exampleskin 2914 forming (e.g., forming all or part of) an outer surface of thefirst wing 2904, and the second wing 2906 includes an example skin 2916forming (e.g., forming all or part of) an outer surface of the secondwing 2906.

The first wing 2904 of FIGS. 29 and 30 defines an example spanwisedirection 2918 moving from an example inboard portion 2920 (e.g.,inboard relative to the spanwise location of the first fence 2908) ofthe first wing 2904 toward an example outboard portion 2922 (e.g.,outboard relative to the spanwise location of the first fence 2908) ofthe first wing 2904. The spanwise direction 2918 defined by the firstwing 2904 is representative of a direction of a spanwise airflow thatmay occur along the first wing 2904. The first wing 2904 also defines anexample chordwise direction 2924 moving from an example leading edge2926 of the first wing 2904 toward an example trailing edge 2928 of thefirst wing 2904. The chordwise direction 2924 defined by the first wing2904 is representative of a direction of a chordwise airflow (e.g., acruise airflow) that may occur along the first wing 2904.

The second wing 2906 of FIGS. 29 and 30 defines an example spanwisedirection 2930 moving from an example inboard portion 2932 (e.g.,inboard relative to the spanwise location of the second fence 2910) ofthe second wing 2906 toward an example outboard portion 2934 (e.g.,outboard relative to the spanwise location of the second fence 2910) ofthe second wing 2906. The spanwise direction 2930 defined by the secondwing 2906 is representative of a direction of a spanwise airflow thatmay occur along the second wing 2906. The second wing 2906 also definesan example chordwise direction 2936 moving from an example leading edge2938 of the second wing 2906 toward an example trailing edge 2940 of thesecond wing 2906. The chordwise direction 2936 defined by the secondwing 2906 is representative of a direction of a chordwise airflow (e.g.,a cruise airflow) that may occur along the second wing 2906.

The first fence 2908 of FIGS. 29 and 30 includes an example base 2942,an example panel 2944, and an example living hinge 2946 extendingbetween the base 2942 and the panel 2944. The base 2942 of the firstfence 2908 is coupled (e.g., fixedly or non-movably coupled) to thefirst wing 2904 of the aircraft 2900. The base 2942 has an examplecentral axis 2948. In the illustrated example of FIGS. 29 and 30, thecentral axis 2948 of the base 2942 is canted (e.g., oriented at anangle) relative to the chordwise direction 2924 of the first wing 2904.For example, as shown in FIGS. 29 and 30, the central axis 2948 of thebase 2942 is canted at an example toe-in angle 2950 relative to thechordwise direction 2924 of the first wing 2904 such that a first end ofthe base 2942 positioned toward the leading edge 2926 of the first wing2904 is located closer to the longitudinal axis 2912 of the aircraft2900 than is a second end of the base 2942 positioned toward thetrailing edge 2928 of the first wing 2904. The example toe-in angle 2950shown in FIGS. 29 and 30 is exaggerated for clarity. When implemented,the toe-in angle 2950 preferably has a value ranging from one to fifteendegrees.

The panel 2944 of the first fence 2908 is coupled to the base 2942 ofthe first fence 2908 via the living hinge 2946 of the first fence 2908such that the panel 2944 is movable (e.g., rotatable) relative to thebase 2942 and/or relative to the first wing 2904 between the stowedposition shown in FIG. 29 and the deployed position shown in FIG. 30.The panel 2944 of the first fence 2908 extends (e.g., in an inboarddirection toward the longitudinal axis 2912) along the skin 2914 of thefirst wing 2904 when the first fence 2908 is in the stowed positionshown in FIG. 29. In some examples, the panel 2944 of the first fence2908 extends along and is positioned over and/or on top of the skin 2914of the first wing 2904 when the first fence 2908 is in the stowedposition shown in FIG. 29. In other examples, the panel 2944 of thefirst fence 2908 extends along and is recessed (e.g., fully or partiallyrecessed) relative to the skin 2914 of the first wing 2904 when thefirst fence 2908 is in the stowed position shown in FIG. 29.

The panel 2944 of the first fence 2908 extends at an upward angle (e.g.,vertically) away from the skin 2914 of the first wing 2904 when thefirst fence 2908 is in the deployed position shown in FIG. 30. The panel2944 of the first fence 2908 is configured to impact the airflow aroundthe aircraft 2900 when the first fence 2908 is in the deployed positionshown in FIG. 30. For example, the panel 2944 can impede a spanwiseairflow occurring along the spanwise direction 2918 of the first wing2904 when the first fence 2908 is in the deployed position shown in FIG.30. As another example, the panel 2944 can initiate and/or generate avortex along the first wing 2904 when the first fence 2908 is in thedeployed position shown in FIG. 30.

The living hinge 2946 of the first fence 2908 extends between the base2942 of the first fence 2908 and the panel 2944 of the first fence 2908.In some examples, the living hinge 2946 has a thickness that is lessthan a thickness of the base 2942, and/or less than a thickness of thepanel 2944. The living hinge 2946 of the first fence 2908 is flexible,and enables and/or causes the panel 2944 of the first fence 2908 ofFIGS. 29 and 30 to move between the stowed position shown in FIG. 29 andthe deployed position shown in FIG. 30. In the illustrated example ofFIGS. 29 and 30, the living hinge 2946 of the first fence 2908 biasesthe panel 2944 of the first fence 2908 to the deployed position shown inFIG. 30.

The panel 2944 of the first fence 2908 of FIGS. 29 and 30 is configuredto move from the deployed position shown in FIG. 30 to the stowedposition shown in FIG. 29 in response to an aerodynamic force exerted onthe panel 2944 of the first fence 2908. In some examples, theaerodynamic force may be generated via a chordwise airflow (e.g., acruise airflow) occurring along the chordwise direction 2924 of thefirst wing 2904. In some examples, the living hinge 2946 of the firstfence 2908 biases and/or maintains the panel 2944 of the first fence2908 in the deployed position shown in FIG. 30 in response to theaerodynamic force exerted on the panel 2944 of the first fence 2908being less than a threshold force value (e.g., less than the biasingforce generated by the living hinge 2946). In some disclosed examples,the panel 2944 of the first fence 2908 moves from the deployed positionshown in FIG. 30 to the stowed position shown in FIG. 29 in response tothe aerodynamic force exerted on the panel 2944 of the first fence 2908being greater than the threshold force value (e.g., greater than thebiasing force generated by the living hinge 2946).

In some disclosed examples, the panel 2944 of the first fence 2908 isconfigured to move from the deployed position shown in FIG. 30 to thestowed position shown in FIG. 29 during a cruise operation of theaircraft 2900 having a first speed, and the panel 2944 of the firstfence 2908 is further configured to move from the stowed position shownin FIG. 29 to the deployed position shown in FIG. 30 during a reducedspeed operation (e.g., a takeoff or landing operation) of the aircraft2900 having a second speed less than the first speed.

The second fence 2910 of FIGS. 29 and 30 includes an example base 2952,an example panel 2954, and an example living hinge 2956 extendingbetween the base 2952 and the panel 2954. The base 2952 of the secondfence 2910 is coupled (e.g., fixedly or non-movably coupled) to thesecond wing 2906 of the aircraft 2900. The base 2952 has an examplecentral axis 2958. In the illustrated example of FIGS. 29 and 30, thecentral axis 2958 of the base 2952 is canted (e.g., oriented at anangle) relative to the chordwise direction 2936 of the second wing 2906.For example, as shown in FIGS. 29 and 30, the central axis 2958 of thebase 2952 is canted at an example toe-in angle 2960 relative to thechordwise direction 2936 of the second wing 2906 such that a first endof the base 2952 positioned toward the leading edge 2938 of the secondwing 2906 is located closer to the longitudinal axis 2912 of theaircraft 2900 than is a second end of the base 2952 positioned towardthe trailing edge 2940 of the second wing 2906. The example toe-in angle2960 shown in FIGS. 29 and 30 is exaggerated for clarity. Whenimplemented, the toe-in angle 2960 preferably has a value ranging fromone to fifteen degrees.

The panel 2954 of the second fence 2910 is coupled to the base 2952 ofthe second fence 2910 via the living hinge 2956 of the second fence 2910such that the panel 2954 is movable (e.g., rotatable) relative to thebase 2952 and/or relative to the second wing 2906 between the stowedposition shown in FIG. 29 and the deployed position shown in FIG. 30.The panel 2954 of the second fence 2910 extends (e.g., in an inboarddirection toward the longitudinal axis 2912) along the skin 2916 of thesecond wing 2906 when the second fence 2910 is in the stowed positionshown in FIG. 29. In some examples, the panel 2954 of the second fence2910 extends along and is positioned over and/or on top of the skin 2916of the second wing 2906 when the second fence 2910 is in the stowedposition shown in FIG. 29. In other examples, the panel 2954 of thesecond fence 2910 extends along and is recessed (e.g., fully orpartially recessed) relative to the skin 2916 of the second wing 2906when the second fence 2910 is in the stowed position shown in FIG. 29.

The panel 2954 of the second fence 2910 extends at an upward angle(e.g., vertically) away from the skin 2916 of the second wing 2906 whenthe second fence 2910 is in the deployed position shown in FIG. 30. Thepanel 2954 of the second fence 2910 is configured to impact the airflowaround the aircraft 2900 when the second fence 2910 is in the deployedposition shown in FIG. 30. For example, the panel 2954 can impede aspanwise airflow occurring along the spanwise direction 2930 of thesecond wing 2906 when the second fence 2910 is in the deployed positionshown in FIG. 30. As another example, the panel 2954 can initiate and/orgenerate a vortex along the second wing 2906 when the second fence 2910is in the deployed position shown in FIG. 30.

The living hinge 2956 of the second fence 2910 extends between the base2952 of the second fence 2910 and the panel 2954 of the second fence2910. In some examples, the living hinge 2956 has a thickness that isless than a thickness of the base 2952, and/or less than a thickness ofthe panel 2954. The living hinge 2956 of the second fence 2910 isflexible, and enables and/or causes the panel 2954 of the second fence2910 of FIGS. 29 and 30 to move between the stowed position shown inFIG. 29 and the deployed position shown in FIG. 30. In the illustratedexample of FIGS. 29 and 30, the living hinge 2946 of the second fence2910 biases the panel 2954 of the second fence 2910 to the deployedposition shown in FIG. 30.

The panel 2954 of the second fence 2910 of FIGS. 29 and 30 is configuredto move from the deployed position shown in FIG. 30 to the stowedposition shown in FIG. 29 in response to an aerodynamic force exerted onthe panel 2954 of the second fence 2910. In some examples, theaerodynamic force may be generated via a chordwise airflow (e.g., acruise airflow) occurring along the chordwise direction 2936 of thesecond wing 2906. In some examples, the living hinge 2956 of the secondfence 2910 biases and/or maintains the panel 2954 of the second fence2910 in the deployed position shown in FIG. 30 in response to theaerodynamic force exerted on the panel 2954 of the second fence 2910being less than a threshold force value (e.g., less than the biasingforce generated by the living hinge 2956). In some disclosed examples,the panel 2954 of the second fence 2910 moves from the deployed positionshown in FIG. 30 to the stowed position shown in FIG. 29 in response tothe aerodynamic force exerted on the panel 2954 of the second fence 2910being greater than the threshold force value (e.g., greater than thebiasing force generated by the living hinge 2956).

In some disclosed examples, the panel 2954 of the second fence 2910 isconfigured to move from the deployed position shown in FIG. 30 to thestowed position shown in FIG. 29 during a cruise operation of theaircraft 2900 having a first speed, and the panel 2954 of the secondfence 2910 is further configured to move from the stowed position shownin FIG. 29 to the deployed position shown in FIG. 30 during a reducedspeed operation (e.g., a takeoff or landing operation) of the aircraft2900 having a second speed less than the first speed.

FIGS. 31-36 provide additional views of the first example fence 2908 ofFIGS. 29 and 30 coupled to the first example wing 2904 of FIGS. 29 and30. More specifically, FIG. 31 is a cross-sectional view of the firstexample fence 2908 of FIGS. 29 and 30 looking inboard and taken acrossthe example central axis 2948 of the example base 2942, with the firstfence 2908 in the example stowed position of FIG. 29. FIG. 32 is afrontal view of the first example fence 2908 of FIGS. 29-31 lookingrearward along the example central axis 2948 of the example base 2942,with the first fence 2908 in the example stowed position of FIGS. 29 and31. FIG. 33 is a plan view of the first example fence 2908 of FIGS.29-32 in the example stowed position of FIGS. 29, 31 and 32. FIG. 34 isa cross-sectional view of the first example fence 2908 of FIGS. 29-33looking inboard and taken across the example central axis 2948 of theexample base 2942, with the first fence 2908 in the example deployedposition of FIG. 30. FIG. 35 is a frontal view of the first examplefence 2908 of FIGS. 29-34 looking rearward along the example centralaxis 2948 of the example base 2942, with the first fence 2908 in theexample deployed position of FIGS. 30 and 34. FIG. 36 is a plan view ofthe first example fence 2908 of FIGS. 29-35 in the example deployedposition of FIGS. 30, 34 and 35.

In the illustrated example of FIGS. 31-36, the base 2942 of the firstfence 2908 is coupled (e.g., fixedly or non-movably coupled) to thefirst wing 2904 of the aircraft 2900. For example, the base 2942 of thefirst fence 2908 can be coupled to the first wing 2904 via one or morefastener(s) that can include one or more mechanical fastener(s) (e.g.,rivet(s), screw(s), bolt(s), pin(s), etc.) and/or one or more chemicalfastener(s) (e.g., glue(s), epox(ies), bonding agent(s), etc.), and/orany combination thereof. The base 2942 of the first fence 2908 includesa first example end 3102, and further includes a second example end 3104located opposite the first end 3102. The first end 3102 of the base 2942is positioned toward the leading edge 2926 of the first wing 2904, andthe second end 3104 of the base 2942 is positioned toward the trailingedge 2928 of the first wing 2904.

In the illustrated example of FIGS. 31-36, the panel 2944 of the firstfence 2908 extends in an inboard direction (e.g., toward thelongitudinal axis 2912 of the aircraft 2900) along the skin 2914 of thefirst wing 2904 when the first fence 2908 is in the stowed positionshown in FIGS. 31-33. As shown in FIGS. 31-33, the panel 2944 of thefirst fence 2908 extends along and is positioned over and/or on top ofthe skin 2914 of the first wing 2904 when the first fence 2908 is in thestowed position. In other examples, the panel 2944 of the first fence2908 can extend along and be recessed (e.g., fully or partiallyrecessed) relative to the skin 2914 of the first wing 2904 when thefirst fence 2908 is in the stowed position. As shown in FIGS. 34-36, thepanel 2944 of the first fence 2908 extends at an upward angle (e.g.,vertically) away from the skin 2914 of the first wing 2904 when thefirst fence 2908 is in the deployed position. The panel 2944 of thefirst fence 2908 is configured to impact the airflow around the aircraft2900 when the first fence 2908 is in the deployed position shown inFIGS. 34-36. For example, the panel 2944 can impede a spanwise airflowoccurring along the spanwise direction 2918 of the first wing 2904 whenthe first fence 2908 is in the deployed position shown in FIGS. 34-36.As another example, the panel 2944 can initiate and/or generate a vortexalong the first wing 2904 when the first fence 2908 is in the deployedposition shown in FIGS. 34-36.

In the illustrated example of FIGS. 31-36, the panel 2944 of the firstfence 2908 is planar. In other examples, the panel 2944 of the firstfence 2908 can be non-planar. For example, the panel 2944 of the firstfence 2908 can have a non-planar (e.g., curved) aerodynamic shape. Insome examples, the non-planar aerodynamic shape can be configured tomatch and/or mimic a non-planar (e.g., curved) aerodynamic shape of thefirst wing 2904. In the illustrated example of FIGS. 31-36, the panel2944 of the first fence 2908 has a trapezoidal shape between the firstend 3102 of the base 2942 and the second end 3104 of the base 2942. Inother examples, the panel 2944 of the first fence 2908 can have adifferent (e.g., non-trapezoidal) shape between the first end 3102 ofthe base 2942 and the second end 3104 of the base 2942. For example, thepanel 2944 of the first fence 2908 can have any of a rectangular shape,a square shape, a triangular shape, a semicircular shape, a circularshape, or an elliptical shape, among others, between the first end 3102of the base 2942 and the second end 3104 of the base 2942.

In the illustrated example of FIGS. 31-36, the living hinge 2946 of thefirst fence 2908 function(s) and/or operate(s) as an actuator configuredto move the panel 2944 of the first fence 2908 between the stowedposition shown in FIGS. 31-33 and the deployed position shown in FIGS.34-36, dependent upon the direction and/or strength of airflows caughtby and/or received at the panel 2944 of the first fence 2908. The livinghinge 2946 of the first fence 2908 extends between the base 2942 of thefirst fence 2908 and the panel 2944 of the first fence 2908. As shown inFIGS. 32 and 35, the living hinge 2946 has a thickness that is less thana thickness of the base 2942, and less than a thickness of the panel2944. The living hinge 2946 of the first fence 2908 is flexible, andenables and/or causes the panel 2944 of the first fence 2908 to movebetween the stowed position shown in FIGS. 31-33 and the deployedposition shown in FIGS. 34-36.

In the illustrated example of FIGS. 31-36, the living hinge 2946 of thefirst fence 2908 biases the panel 2944 of the first fence 2908 to thedeployed position shown in FIGS. 34-36. For example, the living hinge2946 generates a restoring force (e.g., a biasing force) having arestoring force value. In the absence of a deflecting force (e.g., acounter-biasing force, as may be generated via a chordwise and/or cruiseairflow) opposing the restoring force and having a deflecting forcevalue that is greater than the restoring force value, the restoringforce generated via the living hinge 2946 moves (e.g., rotates) thepanel 2944 of the first fence 2908 to, and/or maintains the panel 2944of the first fence 2908 in, the deployed position shown in FIGS. 34-36.

In the illustrated example of FIGS. 31-36, the living hinge 2946 is in arelatively less flexed and/or curved state when the panel 2944 of thefirst fence 2908 is in the stowed position shown in FIGS. 31-33 comparedto when the panel 2944 of the first fence 2908 is in the deployedposition shown in FIGS. 34-36. Conversely, the living hinge 2946 is in arelatively more flexed and/or curved state when the panel 2944 of thefirst fence 2908 is in the deployed position shown in FIGS. 34-36compared to when the panel 2944 of the first fence 2908 is in the stowedposition shown in FIGS. 31-33. Stated differently, the living hinge 2946flexes, bends and/or curls away from the skin 2914 of the first wing2904 as the panel 2944 of the first fence 2908 moves from the stowedposition shown in FIGS. 31-33 to the deployed position shown in FIGS.34-36, and the living hinge 2946 conversely unflexes, unbends and/oruncurls toward the skin 2914 of the first wing 2904 as the panel 2944 ofthe first fence 2908 moves from the deployed position shown in FIGS.34-36 to the stowed position shown in FIGS. 31-33.

Movement (e.g., rotation) of the panel 2944 of the first fence 2908relative to the base 2942 of the first fence 2908 via the living hinge2946 of the first fence 2908 (e.g., which also results in movement ofthe panel 2944 relative to the first wing 2904) is airflow dependent.For example, as described above in connection with FIGS. 29 and 30 andfurther shown in FIGS. 31-360, the central axis 2948 of the base 2942 ofthe first fence 2908 is canted at the toe-in angle 2950 relative to thechordwise direction 2924 of the first wing 2904. Positioning and/ororienting the central axis 2948 of the base 2942 at the toe-in angle2950 causes the panel 2944 of the first fence 2908 to be positionedand/or oriented in a similar manner. When the panel 2944 of the firstfence 2908 is in the deployed position shown in FIGS. 34-36 (e.g., asmay be caused by the restoring force generated by the living hinge 2946of the first fence 2908), the panel 2944 of the first fence 2908 ispositioned to catch, receive and/or react to a chordwise airflow (e.g.,a cruise airflow) occurring along the chordwise direction 2924 of thefirst wing 2904. As a result of the toe-in angle 2950 at which thecentral axis 2948 of the base 2942 is canted, the chordwise airflowoccurring along the chordwise direction 2924 of the first wing 2904carries a deflecting force component that counteracts (e.g., opposes)the restoring force generated by the living hinge 2946 of the firstfence 2908.

If the deflecting force component of the chordwise airflow received at,applied to, and/or exerted on the panel 2944 of the first fence 2908 isgreater than the restoring force generated by the living hinge 2946 ofthe first fence 2908, the chordwise airflow moves the panel 2944 of thefirst fence 2908 from the deployed position shown in FIGS. 34-36 to thestowed position shown in FIGS. 31-33. If the deflecting force componentof the chordwise airflow received at, applied to, and/or exerted on thepanel 2944 of the first fence 2908 is instead less than the restoringforce generated by the living hinge 2946 of the first fence 2908, theliving hinge 2946 maintains the panel 2944 of the first fence 2908 inthe deployed position shown in FIGS. 34-36, and/or moves the panel 2944of the first fence 2908 from the stowed position shown in FIGS. 31-33 tothe deployed position shown in FIGS. 34-36. Movement of the panel 2944of the first fence 2908 relative to the base 2942 of the first fence2908, and/or relative to the first wing 2904, is accordingly dependenton the presence or absence of the chordwise airflow, and on the relativestrength (e.g., force) of such airflow.

In some examples, the panel 2944 of the first fence 2908 is configuredto move from the deployed position shown in FIGS. 34-36 to the stowedposition shown in FIGS. 31-33 during a cruise operation of the aircraft2900 having a first speed, and the panel 2944 of the first fence 2908 isfurther configured to move from the stowed position of FIGS. 31-33 tothe deployed position of FIGS. 34-36 during a reduced speed operation(e.g., a takeoff or landing operation) of the aircraft 2900 having asecond speed less than the first speed. For example, the living hinge2946 of the first fence 2908 may be configured and/or implemented tohave a flexing, bending and/or curling moment that causes the livinghinge 2946 to generate a restoring force sufficient to move the panel2944 of the first fence 2908 to, and/or sufficient to maintain the panel2944 of the first fence 2908 in, the deployed position shown in FIGS.34-36 when the aircraft 2900 is traveling at a speed less than a speedthreshold (e.g., less than a cruise speed). When the aircraft 2900 istraveling at a speed above or equal to the speed threshold, therestoring force generated by the living hinge 2946 of the first fence2908 is overcome via a deflecting force, and the panel 2944 of the firstfence 2908 accordingly moves from the deployed position shown in FIGS.34-36 to the stowed position shown in FIGS. 31-33.

While FIGS. 31-36 and the descriptions thereof provided above aredirected to the actuator of the first fence 2908 being implemented as aliving hinge (e.g., living hinge 2946) configured to bias and/or movethe panel 2944 of the first fence 2908 from the stowed position shown inFIGS. 31-33 to the deployed position shown in FIGS. 34-36, the actuatorof the first fence 2908 can be implemented in other forms including, forexample, electrical, hydraulic, pneumatic, motor-driven, and/or shapememory alloy actuators. Furthermore, while FIGS. 31-36 and thedescriptions thereof provided above are directed to the first fence 2908of FIGS. 29 and 30 that is coupled to the first wing 2904 of FIGS. 29and 30, the informed reader will recognize that the second fence 2910 ofFIGS. 29 and 30 that is coupled to the second wing 2906 of FIGS. 29 and30 can be similarly implemented (e.g., in a manner that is mirroredabout the longitudinal axis 2912 of the aircraft 2900). Moreover, whileFIGS. 31-36 and the descriptions thereof provided above are directed tothe first fence 2908 of FIGS. 29 and 30 that is coupled to the firstwing 2904 of FIGS. 29 and 30, the informed reader will recognize thatany number of additional fences can be similarly implemented on thefirst wing 2904. Moreover, while FIGS. 29-36 and the descriptionsthereof provided above disclose the first fence 2908 of FIGS. 29-36being implemented and/or configured in a manner that generally conformsand/or corresponds to the structures(s) and/or orientation(s) associatedwith the first fence 108 of FIGS. 1-10, the informed reader will furtherrecognize that the first fence 2908 of FIGS. 29-36 can alternatively beimplemented and/or configured in a manner that conforms and/orcorresponds to the structure(s) and/or orientations(s) associated withthe first fence 1108 of FIGS. 11-20, or the first fence 2108 of FIGS.21-28.

In some examples, implementing any of the above-described fences (e.g.,the first fence 108 of FIGS. 1-10, the first fence 1108 of FIGS. 11-20,the first fence 2108 of FIGS. 21-28, the first fence 2908 of FIGS.29-36, etc.) as a fence having a single, planar panel may in someinstances become problematic with regard to stowing the fence along theskin of the wing of the aircraft, particularly when the wing is a curvedwing having a substantial degree of curvature. For example, FIG. 37 is across-sectional view of an example fence 3702 having a single exampleplanar panel 3704 positioned in an example stowed position relative toan example curved wing 3706. The curved wing 3706 has an example chord3708 extending from an example leading edge 3710 of the curved wing 3706to an example trailing edge 3712 of the curved wing 3706. The planarpanel 3704 is oriented at an example angle 3714 relative to the chord3708. The planar panel 3704 includes a first example end 3716 positionedtoward the leading edge 3710 of the curved wing 3706, a second exampleend 3718 located opposite the first end 3716 and positioned toward thetrailing edge 3712 of the curved wing 3706, and an example middleportion 3720 located between the first and second ends 3716, 3718 of theplanar panel 3704.

As shown in FIG. 37, although the middle portion 3720 of the planarpanel 3704 is adjacent the curved wing 3706 when the fence 3702 is inthe stowed position, the curvature of the curved wing 3706 prevents thefirst and second ends 3716, 3718 of the planar panel 3704 from beingadjacent the curved wing 3706. The illustrated spacing and/or separationbetween the first and second ends 3716, 3718 of the planar panel 3704and the curved wing 3706 of FIG. 37 can result in undesirableaerodynamic performance penalties (e.g., drag) when the fence 3702 is inthe stowed position. In some examples, such undesirable aerodynamicperformance penalties can advantageously be reduced by alternativelyimplementing the fence 3702 of FIG. 37 as a fence having a plurality ofplanar panels.

For example, FIG. 38 is a cross-sectional view of an example fence 3802having a plurality of example planar panels 3804 respectively positionedin corresponding example stowed positions relative to an example curvedwing 3806. The curved wing 3806 has an example chord 3808 extending froman example leading edge 3810 of the curved wing 3806 to an exampletrailing edge 3812 of the curved wing 3806. In the illustrated exampleof FIG. 38, the planar panels 3804 of the fence 3802 include a firstexample planar panel 3814, a second example planar panel 3816, a thirdexample planar panel 3818, a fourth example planar panel 3820, and afifth example planar panel 3822. In other examples, the fence 3802 caninclude a different number of planar panels (e.g., 2, 3, 4, 6, 8, 10,etc.).

The first planar panel 3814 of FIG. 38 is oriented at a first exampleangle 3824 relative to the chord 3808. The second planar panel 3816 ofFIG. 38 is located aft of the first planar panel 3814 and is oriented ata second example angle 3826 relative to the chord 3808. The third planarpanel 3818 of FIG. 38 is located aft of the second planar panel 3816 andis oriented at a third example angle 3828 relative to the chord 3808.The fourth planar panel 3820 of FIG. 38 is located aft of the thirdplanar panel 3818 and is oriented at a fourth example angle 3830relative to the chord 3808. The fifth planar panel 3822 of FIG. 38 islocated aft of the fourth planar panel 3820 and is oriented at a fifthexample angle 3832 relative to the chord 3808.

In the illustrated example of FIG. 38, some or all of the first, second,third, fourth and fifth angles 3824, 3826, 3828, 3830, 3832 differ fromone another, with the differing angles corresponding to and/or beingdetermined based on the respective local curvatures of the skin of thecurved wing 3806 adjacent the respective locations of the first, second,third, fourth and fifth planar panels 3814, 3816, 3818, 3820, 3822. As aresult, the first, second, third, fourth and fifth planar panels 3814,3816, 3818, 3820, 3822 collectively match and or mimic the overallcurvature of the curved wing 3806 when the first, second, third, fourthand fifth planar panels 3814, 3816, 3818, 3820, 3822 are in theirrespective stowed positions. For example, respective ones of the first,second, third, fourth and fifth planar panels 3814, 3816, 3818, 3820,3822 of FIG. 38 demonstrate less separation from the curved wing 3806compared to the separation demonstrated by the single planar panel 3704relative to the curved wing 3706 of FIG. 37 described above. Suchdecreased separation in turn reduces the undesirable aerodynamicperformance penalties that can be associated with implementing a fencehaving a single planar panel.

FIG. 39 is a cross-sectional view of the example fence 3802 of FIG. 38having the plurality of example planar panels 3804 (e.g., the first,second, third, fourth and fifth planar panels 3814, 3816, 3818, 3820,3822) respectively positioned in corresponding example deployedpositions relative to the example curved wing 3806 of FIG. 38. Thefirst, second, third, fourth and fifth planar panels 3814, 3816, 3818,3820, 3822 of the fence 3802 are individually and collectivelyconfigured to impede a spanwise airflow along the curved wing 3806 whenthe fence 3802 is in the deployed position of FIG. 39. In theillustrated example of FIGS. 38 and 39, each of the first, second,third, fourth and fifth planar panels 3814, 3816, 3818, 3820, 3822 ofthe fence 3802 may be individually movable and/or actuatable. Forexample, each of the first, second, third, fourth and fifth planarpanels 3814, 3816, 3818, 3820, 3822 of the fence 3802 can be operativelycoupled to a separate corresponding spring-loaded axle. The informedreader will recognize that respective ones of the correspondingspring-loaded axles may be implemented using any of the above-describedspring-loaded axles (e.g., the spring-loaded axle 316 of FIGS. 3-10, thespring-loaded axle 1316 of FIGS. 13-20, the spring-loaded axle 2316 ofFIGS. 23-28, etc.). As another example, each of the first, second,third, fourth and fifth planar panels 3814, 3816, 3818, 3820, 3822 ofthe fence 3802 can be operatively coupled to a separate correspondingliving hinge and/or base. The informed reader will recognize thatrespective ones of the corresponding living hinges and/or bases may beimplemented using the above-described living hinge 2946 and/or base 2942of FIGS. 29-36.

In some examples, any of the above-described panel(s) and/or, moregenerally, any of the above-described fences (e.g., the first fence 108of FIGS. 1-10, the first fence 1108 of FIGS. 11-20, the first fence 2108of FIGS. 21-28, the first fence 2908 of FIGS. 29-36, the fence 3802 ofFIGS. 38 and 39, etc.) can be implemented such that the panel and/orfence extends along and is recessed (e.g., fully or partially recessed)relative to the surrounding skin of the wing when the fence is in itsstowed position. For example, FIG. 40 is a cross-sectional view of anexample fence 4002 having a plurality of example panels 4004respectively positioned in corresponding example recessed stowedpositions relative to an example wing 4006. The wing 4006 includes anexample supporting structure 4008 (e.g., a spar) located between anexample leading edge 4010 and an example trailing edge 4012 of the wing4006. In the illustrated example of FIG. 40, the panels 4004 of thefence 4002 include a first example panel 4014, a second example panel4016, a third example panel 4018, and a fourth example panel 4020. Thefirst panel 4014 is located forward of the supporting structure 4008.The second panel 4016 is located aft of the first panel 4014 and forwardof the supporting structure 4008. The third panel 4018 is located aft ofthe second panel 4016 and aft of the supporting structure 4008. Thefourth panel 4020 is located aft of the third panel 4018 and aft of thesupporting structure 4008. In other examples, the fence 4002 can includea different number of panels (e.g., 2, 3, 5, 6, 8, 10, etc.), and thepanels may be arranged at different locations relative to the supportingstructure 4008.

As shown in FIG. 40, each of the first, second, third and fourth panels4014, 4016, 4018, 4020 has a respective stowed position in which thepanel of the fence 4002 is recessed within the wing 4006 (e.g., recessedrelative to the skin of the wing 4006). In some examples, each of thefirst, second, third and fourth panels 4014, 4016, 4018, 4020 canrespectively be recessed within the wing 4006 such that the panel, aswell as any axle(s), axle mount(s), spring(s), living hinge(s) and/orbase(s) coupled to the panel and/or, more generally, coupled to thefence 4002, is/are recessed (e.g., fully or partially recessed) relativeto the surrounding skin of the wing 4006 when the fence 4002 is in itsstowed position. Recessing such components within the wing 4006 canfurther reduce drag associated with the fence 4002 when the fence 4002is stowed.

FIG. 41 is a cross-sectional view of the example fence 4002 of FIG. 40having the plurality of example panels 4004 respectively positioned incorresponding example deployed positions relative to the example wing4006 of FIG. 40. As shown in FIG. 41, each of the first, second, thirdand fourth panels 4014, 4016, 4018, 4020 has a respective deployedposition in which the panel of the fence 4002 extends upwardly from thewing 4006 (e.g., extends upwardly relative to the skin of the wing4006). In some examples, the fence 4002 of FIGS. 40 and 41 can furtherinclude a non-recessed panel positioned over the supporting structure4008 of the wing 4006. In still other examples, the fence 4002 of FIGS.40 and 41 can additionally or alternatively include one or morenon-recessed panel(s) located at the leading edge 4010 and/or at thetrailing edge 4012 of the wing 4006.

From the foregoing, it will be appreciated that exampleairflow-dependent deployable fences for aircraft wings have beendisclosed. Unlike the conventional fences and/or other countermeasuresdescribed above, the example deployable fences disclosed herein areaerodynamically activated and/or airflow dependent. In some disclosedexamples, a deployable fence is coupled (e.g., rotatably coupled) to awing of an aircraft such that the fence is advantageously movablerelative to the wing between a stowed position in which a panel of thefence extends along a skin of the wing, and a deployed position in whichthe panel extends at an upward angle away from the skin. The panel isconfigured to impact the airflow around the aircraft when the fence isin the deployed position. For example, the panel can impede a spanwiseairflow along the wing when the fence is in the deployed position. Asanother example, the panel can initiate and/or generate a vortex alongthe wing when the fence is in the deployed position. The fence isadvantageously configured to move between the stowed position and thedeployed position in response to an aerodynamic force exerted on thefence. In some disclosed examples, the fence is configured to move fromthe deployed position to the stowed position in response to anaerodynamic force exerted on the panel. In other disclosed examples, thefence is configured to move from the stowed position to the deployedposition in response to an aerodynamic force exerted on a deploymentvane of the fence.

The example airflow-dependent deployable fences disclosed herein providenumerous advantages over the conventional fences described above. Forexample, the movability (e.g., movement from a deployed position to astowed position) of the airflow-dependent deployable fences disclosedherein advantageously reduces undesirable aerodynamic performancepenalties (e.g., drag) during high-speed operation of the aircraft(e.g., during cruise). As another example, the airflow-dependentdeployable fences disclosed herein provide a stowed position for thefence whereby the fence extends along the skin of the wing (as opposedto vertically within the wing), thereby advantageously increasing theamount of unused space within the wing relative to the amount of spacethat may otherwise be consumed by the in-wing mechanical linkagesassociated with the above-described vertically-deployable conventionalfences. As yet another example, the airflow-dependent deployable fencesdisclosed herein facilitate pilot-free operation (e.g., deployment andretraction) of the fences, which advantageously ensures that the fencesare deployed and/or retracted at the appropriate time(s) and/or underthe appropriate flight condition(s).

In some examples, an apparatus is disclosed. In some disclosed examples,the apparatus comprises a fence coupled to a wing of an aircraft. Insome disclosed examples, the fence is movable relative to the wingbetween a stowed position in which a panel of the fence extends along askin of the wing, and a deployed position in which the panel extends atan upward angle away from the skin. In some disclosed examples, thepanel is configured to impede a spanwise airflow along the wing when thefence is in the deployed position. In some disclosed examples, the fenceis configured to move from the deployed position to the stowed positionin response to an aerodynamic force exerted on the panel.

In some disclosed examples, the panel is further configured to generatea vortex along the wing when the fence is in the deployed position.

In some disclosed examples, the apparatus further comprises an actuatorconfigured to move the fence from the stowed position to the deployedposition.

In some disclosed examples, the actuator is configured to move the fencefrom the stowed position to the deployed position in response to theaerodynamic force being less than a threshold force value.

In some disclosed examples, the fence is configured to move from thedeployed position to the stowed position during a cruise operation ofthe aircraft having a first speed. In some disclosed examples, the fenceis further configured to move from the stowed position to the deployedposition during a reduced speed operation of the aircraft having asecond speed less than the first speed.

In some disclosed examples, the actuator includes a spring-loaded axleoperatively coupled to the fence and mounted to the wing. In somedisclosed examples, the spring-loaded axle includes an axle and a springcoiled around the axle.

In some disclosed examples, the spring is configured to wind around theaxle in response to the aerodynamic force being greater than thethreshold force value. In some disclosed examples, the spring is furtherconfigured to unwind around the axle in response to the aerodynamicforce being less than the threshold force value.

In some disclosed examples, the axle has a central axis that is cantedrelative to a chordwise direction of the wing.

In some disclosed examples, the central axis is canted at a toe-in anglerelative to the chordwise direction of the wing. In some disclosedexamples, the panel extends in an inboard direction away from thecentral axis when the fence is in the stowed position.

In some disclosed examples, the central axis is canted at a toe-outangle relative to the chordwise direction of the wing. In some disclosedexamples, the panel extends in an outboard direction away from thecentral axis when the fence is in the stowed position.

In some disclosed examples, the panel is recessed within the wing whenthe fence is in the stowed position.

In some disclosed examples, the panel includes a first panel locatedadjacent a first portion of the skin. In some disclosed examples, thefirst portion of the skin has a first orientation relative to a chord ofthe wing. In some disclosed examples, the first panel is configured tobe oriented along the first portion of the skin when the fence is in thestowed position. In some disclosed examples, the panel further includesa second panel located aft of the first panel and adjacent a secondportion of the skin located aft of the first portion. In some disclosedexamples, the second portion of the skin has a second orientationrelative to the chord of the wing that differs from the firstorientation. In some disclosed examples, the second panel is configuredto be oriented along the second portion of the skin when the fence is inthe stowed position. In some disclosed examples, the first panel and thesecond panel are configured to impede the spanwise airflow along thewing when the fence is in the deployed position.

In some examples, a method for moving a fence coupled to a wing of anaircraft is disclosed. In some disclosed examples, the method comprisesmoving the fence between a stowed position in which a panel of the fenceextends along a skin of the wing, and a deployed position in which thepanel extends at an upward angle away from the skin. In some disclosedexamples, the panel impedes a spanwise airflow along the wing when thefence is in the deployed position. In some disclosed examples, themoving includes moving the fence from the deployed position to thestowed position in response to an aerodynamic force exerted on thepanel.

In some disclosed examples, the panel generates a vortex along the wingwhen the fence is in the deployed position.

In some disclosed examples, the aerodynamic force is generated via asubstantially chordwise airflow along a chordwise direction of the wing.

In some disclosed examples, the fence is rotatably coupled to the wingvia an axle having a central axis that is canted relative to thechordwise direction of the wing.

In some disclosed examples, the central axis is canted at a toe-in anglerelative to the chordwise direction of the wing. In some disclosedexamples, the panel extends in an inboard direction away from thecentral axis when the fence is in the stowed position.

In some disclosed examples, the central axis is canted at a toe-outangle relative to the chordwise direction of the wing. In some disclosedexamples, the panel extends in an outboard direction away from thecentral axis when the fence is in the stowed position.

In some examples, an apparatus is disclosed. In some disclosed examples,the apparatus comprises a fence coupled to a wing of an aircraft. Insome disclosed examples, the fence is movable relative to the wingbetween a stowed position in which a panel of the fence extends along askin of the wing, and a deployed position in which the panel extends atan upward angle away from the skin. In some disclosed examples, thepanel is configured to impede a spanwise airflow along the wing when thefence is in the deployed position. In some disclosed examples, the fenceis configured to move from the stowed position to the deployed positionin response to an aerodynamic force exerted on a deployment vane of thefence.

In some disclosed examples, the deployment vane is substantiallyorthogonal to the panel.

In some disclosed examples, the panel is further configured to generatea vortex along the wing when the fence is in the deployed position.

In some disclosed examples, the apparatus further comprises an actuatorconfigured to move the fence from the deployed position to the stowedposition.

In some disclosed examples, the actuator is configured to move the fencefrom the deployed position to the stowed position in response to theaerodynamic force being less than a threshold force value.

In some disclosed examples, the actuator includes a spring-loaded axleoperatively coupled to the fence and mounted to the wing. In somedisclosed examples, the spring-loaded axle includes an axle and a springcoiled around the axle.

In some disclosed examples, the spring is configured to wind around theaxle in response to the aerodynamic force being greater than thethreshold force value. In some disclosed examples, the spring is furtherconfigured to unwind around the axle in response to the aerodynamicforce being less than the threshold force value.

In some disclosed examples, the axle has a central axis that issubstantially parallel to a chordwise direction of the wing.

In some disclosed examples, the panel extends in an inboard directionaway from the central axis when the fence is in the stowed position.

In some disclosed examples, the deployment vane extends in an outboarddirection away from the central axis when the fence is in the deployedposition.

In some disclosed examples, the panel is recessed within the wing whenthe fence is in the stowed position.

In some disclosed examples, the panel includes a first panel locatedadjacent a first portion of the skin. In some disclosed examples, thefirst portion of the skin has a first orientation relative to a chord ofthe wing. In some disclosed examples, the first panel is configured tobe oriented along the first portion of the skin when the fence is in thestowed position. In some disclosed examples, the panel further includesa second panel located aft of the first panel and adjacent a secondportion of the skin located aft of the first portion. In some disclosedexamples, the second portion of the skin has a second orientationrelative to the chord of the wing that differs from the firstorientation. In some disclosed examples, the second panel is configuredto be oriented along the second portion of the skin when the fence is inthe stowed position. In some disclosed examples, the first panel and thesecond panel are configured to impede the spanwise airflow along thewing when the fence is in the deployed position.

In some examples, a method for moving a fence coupled to a wing of anaircraft is disclosed. In some disclosed examples, the method comprisesmoving the fence between a stowed position in which a panel of the fenceextends along a skin of the wing, and a deployed position in which thepanel extends at an upward angle away from the skin. In some disclosedexamples, the panel impedes a spanwise airflow along the wing when thefence is in the deployed position. In some disclosed examples, themoving includes moving the fence from the stowed position to thedeployed position in response to an aerodynamic force exerted on adeployment vane of the fence.

In some disclosed examples, the deployment vane is substantiallyorthogonal to the panel.

In some disclosed examples, the panel generates a vortex along the wingwhen the fence is in the deployed position.

In some disclosed examples, the aerodynamic force is generated via asubstantially spanwise airflow along a spanwise direction of the wing.

In some disclosed examples, the fence is rotatably coupled to the wingvia an axle having a central axis.

In some disclosed examples, the central axis is substantially parallelto a chordwise direction of the wing.

In some disclosed examples, the panel extends in an inboard directionaway from the central axis when the fence is in the stowed position.

In some disclosed examples, the deployment vane extends in an outboarddirection away from the central axis when the fence is in the deployedposition.

In some examples, an apparatus is disclosed. In some disclosed examples,the apparatus comprises a fence of a wing of an aircraft. In somedisclosed examples, the fence includes a base that is coupled to thewing and a panel that is movable relative to the base and the wingbetween a stowed position in which the panel extends along a skin of thewing, and a deployed position in which the panel extends at an upwardangle away from the skin. In some disclosed examples, the panel isconfigured to impede a spanwise airflow along the wing when the panel isin the deployed position. In some disclosed examples, the panel isconfigured to move from the deployed position to the stowed position inresponse to an aerodynamic force exerted on the panel.

In some disclosed examples, the panel is further configured to generatea vortex along the wing when the panel is in the deployed position.

In some disclosed examples, the apparatus further comprises a livinghinge extending between the panel and the base. In some disclosedexamples, the living hinge is configured to move the panel from thestowed position to the deployed position.

In some disclosed examples, the living hinge is configured to move thepanel from the stowed position to the deployed position in response tothe aerodynamic force being less than a threshold force value.

In some disclosed examples, the panel is configured to move from thedeployed position to the stowed position during a cruise operation ofthe aircraft having a first speed. In some disclosed examples, the panelis further configured to move from the stowed position to the deployedposition during a reduced speed operation of the aircraft having asecond speed less than the first speed.

In some disclosed examples, the living hinge is configured to bend awayfrom the skin of the wing as the panel is moved from the stowed positionto the deployed position. In some disclosed examples, the living hingeis further configured to unbend toward the skin of the wing as the panelis moved from the deployed position to the stowed position.

In some disclosed examples, the living hinge is configured to bend awayfrom the skin of the wing in response to the aerodynamic force beingless than the threshold force value. In some disclosed examples, theliving hinge is further configured to unbend toward the skin of the wingin response to the aerodynamic force being greater than the thresholdforce value.

In some disclosed examples, the base has a central axis that is cantedrelative to a chordwise direction of the wing.

In some disclosed examples, the central axis is canted at a toe-in anglerelative to the chordwise direction of the wing. In some disclosedexamples, the panel extends in an inboard direction away from thecentral axis when the panel is in the stowed position.

In some disclosed examples, the central axis is canted at a toe-outangle relative to the chordwise direction of the wing. In some disclosedexamples, the panel extends in an outboard direction away from thecentral axis when the panel is in the stowed position.

In some disclosed examples, the panel is recessed within the wing whenthe panel is in the stowed position.

In some disclosed examples, the panel includes a first panel locatedadjacent a first portion of the skin. In some disclosed examples, thefirst portion of the skin has a first orientation relative to a chord ofthe wing. In some disclosed examples, the first panel is configured tobe oriented along the first portion of the skin when the panel is in thestowed position. In some disclosed examples, the panel further includesa second panel located aft of the first panel and adjacent a secondportion of the skin located aft of the first portion. In some disclosedexamples, the second portion of the skin has a second orientationrelative to the chord of the wing that differs from the firstorientation. In some disclosed examples, the second panel is configuredto be oriented along the second portion of the skin when the panel is inthe stowed position. In some disclosed examples, the first panel and thesecond panel are configured to impede the spanwise airflow along thewing when the panel is in the deployed position.

In some examples, a method for moving a panel of a fence of a wing of anaircraft relative to the wing and relative to a base of the fencecoupled to the wing is disclosed. In some disclosed examples, the methodcomprises moving the panel between a stowed position in which the panelextends along a skin of the wing, and a deployed position in which thepanel extends at an upward angle away from the skin. In some disclosedexamples, the panel impedes a spanwise airflow along the wing when thepanel is in the deployed position. In some disclosed examples, themoving includes moving the panel from the deployed position to thestowed position in response to an aerodynamic force exerted on thepanel.

In some disclosed examples, the panel generates a vortex along the wingwhen the panel is in the deployed position.

In some disclosed examples, the aerodynamic force is generated via asubstantially chordwise airflow along a chordwise direction of the wing.

In some disclosed examples, the fence further includes a living hingeextending between the base and the panel. In some disclosed examples,the base has a central axis that is canted relative to the chordwisedirection of the wing.

In some disclosed examples, the central axis is canted at a toe-in anglerelative to the chordwise direction of the wing. In some disclosedexamples, the panel extends in an inboard direction away from thecentral axis when the panel is in the stowed position.

In some disclosed examples, the central axis is canted at a toe-outangle relative to the chordwise direction of the wing. In some disclosedexamples, the panel extends in an outboard direction away from thecentral axis when the panel is in the stowed position.

Although certain example methods, apparatus and articles of manufacturehave been disclosed herein, the scope of coverage of this patent is notlimited thereto. On the contrary, this patent covers all methods,apparatus and articles of manufacture fairly falling within the scope ofthe claims of this patent.

What is claimed is:
 1. An apparatus comprising: a fence coupled to awing of an aircraft, the fence being movable relative to the wingbetween a stowed position in which a panel of the fence extends along askin of the wing, and a deployed position in which the panel extends atan upward angle away from the skin, the panel configured to impede aspanwise airflow along the wing when the fence is in the deployedposition, the fence configured to move from the stowed position to thedeployed position in response to an aerodynamic force exerted on adeployment vane of the fence.
 2. The apparatus of claim 1, wherein thedeployment vane is substantially orthogonal to the panel.
 3. Theapparatus of claim 1, wherein the panel is further configured togenerate a vortex along the wing when the fence is in the deployedposition.
 4. The apparatus of claim 1, further comprising an actuatorconfigured to move the fence from the deployed position to the stowedposition.
 5. The apparatus of claim 4, wherein the actuator isconfigured to move the fence from the deployed position to the stowedposition in response to the aerodynamic force being less than athreshold force value.
 6. The apparatus of claim 5, wherein the actuatorincludes a spring-loaded axle operatively coupled to the fence andmounted to the wing, the spring-loaded axle including an axle and aspring coiled around the axle.
 7. The apparatus of claim 6, wherein thespring is configured to wind around the axle in response to theaerodynamic force being greater than the threshold force value, and thespring is further configured to unwind around the axle in response tothe aerodynamic force being less than the threshold force value.
 8. Theapparatus of claim 6, wherein the axle has a central axis that issubstantially parallel to a chordwise direction of the wing.
 9. Theapparatus of claim 8, wherein the panel extends in an inboard directionaway from the central axis when the fence is in the stowed position. 10.The apparatus of claim 8, wherein the deployment vane extends in anoutboard direction away from the central axis when the fence is in thedeployed position.
 11. The apparatus of claim 1, wherein the panel isrecessed within the wing when the fence is in the stowed position. 12.The apparatus of claim 1, wherein the panel includes: a first panellocated adjacent a first portion of the skin, the first portion of theskin having a first orientation relative to a chord of the wing, thefirst panel configured to be oriented along the first portion of theskin when the fence is in the stowed position; and a second panellocated aft of the first panel and adjacent a second portion of the skinlocated aft of the first portion, the second portion of the skin havinga second orientation relative to the chord of the wing that differs fromthe first orientation, the second panel configured to be oriented alongthe second portion of the skin when the fence is in the stowed position,the first panel and the second panel configured to impede the spanwiseairflow along the wing when the fence is in the deployed position.
 13. Amethod for moving a fence coupled to a wing of an aircraft, the methodcomprising: moving the fence between a stowed position in which a panelof the fence extends along a skin of the wing, and a deployed positionin which the panel extends at an upward angle away from the skin, thepanel impeding a spanwise airflow along the wing when the fence is inthe deployed position, the moving including moving the fence from thestowed position to the deployed position in response to an aerodynamicforce exerted on a deployment vane of the fence.
 14. The method of claim13, wherein the deployment vane is substantially orthogonal to thepanel.
 15. The method of claim 13, wherein the panel generates a vortexalong the wing when the fence is in the deployed position.
 16. Themethod of claim 13, wherein the aerodynamic force is generated via asubstantially spanwise airflow along a spanwise direction of the wing.17. The method of claim 16, wherein the fence is rotatably coupled tothe wing via an axle having a central axis.
 18. The method of claim 17,wherein the central axis is substantially parallel to a chordwisedirection of the wing.
 19. The method of claim 18, wherein the panelextends in an inboard direction away from the central axis when thefence is in the stowed position.
 20. The method of claim 18, wherein thedeployment vane extends in an outboard direction away from the centralaxis when the fence is in the deployed position.